DEOXYRIBONUCLEIC ACiD - DEPENDENT RIBONUCLEIC ACE) ?’!33LYMERASE OF PSEUDOMONAS PUTIDA: PURIFICATION AND CHARACTERIZATION Thesis for the Degree of Ph. D. MICHIGAN STATE UNIVERSITY JAMES CARL JOHNSON 1971 ‘4““43‘ f“: LID “ " ‘ ;: 1* Michigan. State University This is to certify that the thesis entitled DEOXYRIBONUCLEIC ACID-DEPENDENT RIBONUCLEIC ACID POLYMERASE 0F PSEUDOMONAS PUTIDA: PURIFICATION AND CHARACTERIZATION presented by JAMES CARL JOHNSON has been accepted towards fulfillment of the requirements for 9‘ D degree 1n WO‘Z/ WW 460$)”; Major professor Date 'QM / lf7/ ' II / 0-7639 ABSTRACT DEOXYRIBONUCLEIC ACID-DEPENDENT RIBONUCLEIC ACID POLYMERASE OF PSEUDOMONAS PUTIDA: PURIFICATION AND CHARACTERIZATION BY James Carl Johnson The objectives of this study were to obtain homo- geneous DNA-dependent RNA polymerase from Pseudomonas putida, to determine the size and structure of the enzyme, and to study properties of the enzyme-mediated synthesis of RNA. Two forms of RNA polymerase (nucleoside triphos- phate RNA nucleotidyltransferase, EC 2.7.7.6) from g. putida were resolved by chromatography on phosphocellulose and subsequently purified to greater than 98 per cent of homogeneity. As determined by sodium dodecyl sulfate— polyacrylamide gel electrophoresis, the polypeptide sub- unit structures of the two forms of the enzyme were dZBB'o and azBB'. The molecular weights of polypeptides a, 8, B', and 0 were 44,000, 155,000, 165,000, and 98,000, respec- tively. The sedimentation coefficients of 0288'0 and 0288' as determined by sucrose gradient centrifugation in 0.40 M potassium acetate were 13 S and 12 8, respectively, James Carl Johnson but in 0.05 M potassium acetate, the sedimentation coef- ficients of the aggregate forms of aZBB'o and oZBB' were 19 S and 25 S. Similar results were obtained by analytical ultracentrifugation. Polyacrylamide gel electrophoresis of aZBB'o or of 0288' resulted in several bands of protein. Each protein band was enzymatically active in the unprimed synthesis of poly A-poly U, thereby suggesting that the multiple bands represented aggregate forms of the enzyme. 35S—labeled B. putida RNA polymerase a288'o was purified from labeled cells which had been grown on a I minimal growth medium containing 35S-labeled sulfate. As shown by sodium dodecyl sulfate-polyacrylamide gel electro- phoresis the 35S-labeled-enzyme was at least 98 per cent homogeneous. The specific radioactivity of the enzyme was 7 Cpm per mg of protein. Analysis of 358 content of each polypeptide subunit showed that the amount of 35S 2.3 X 10 0f 8', B, and 0 relative to a was 3.6 to 3.6 to 2.2 to 1.0, respectively. The amount of 8' plus 8 in the Initial thract was 1.2 per cent of the total protein as determined by sodium dodecyl sulfate polyacrylamide gel electrophor- esis. From the amount of 8' plus 8 relative to the total Protein and the formula weight of oZBB'o, it was calculated that there were approximately 5,000 molecules of dzBB'o per E. putida cell. The reaction catalyzed by RNA polymerase was fol- lowed by measuring the incorporation of 3H labeled- ribonucleoside monOphosphates into RNA or by measuring the James Carl Johnson formation of inorganic pyrophosphate. An enzymic method for the determination of inorganic pyrophosphate was developed. Inorganic pyrophosphate was quantitatively determined from the amount of NADPH formed via the action of UDP—glucose pyrophosphorylase, phosphoglucomutase, and glucose-6-phosphate dehydrogenase. The method for the determination of inorganic pyrophosphate was used for the assay of RNA polymerase by coupling the generation of inorganic pyrophosphate by RNA polymerase with NADPH formation. A mole of inorganic pyrophosphate released by RNA polymerase resulted in the reduction of a mole of NADP+. By means of the radioactive assay of RNA polymer- ase or the assay for inorganic pyrophosphate, it was shown that dZBB'o was 4- to 5-fold more active in tran- scribing native bacteriophage gh-l DNA than was 0288'. With denatured DNA or poly d(A-T) as template, aZBB' was twice as active as aZBB'o. The rate of the DNA-directed POlymerization reactions catalyzed by azBB'o in the presence of pancreatic ribonuclease was increased 10 per cent, whereas that rate catalyzed by ozBB' was increased 80 to 110 per cent. DEOXYRIBONUCLEIC ACID-DEPENDENT RIBONUCLEIC ACID POLYMERASE OF PSEUDOMONAS PUTIDA: PURIFICATION AND CHARACTERIZATION BY James Carl Johnson A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Microbiology and Public Health 1971 DEDICATION To my parents who provided the opportunity and encouragement and to my wife who was blessed with patience and understanding. ii ACKNOWLEDGEMENTS , My sincere thanks and appreciation for the help and guidance in all phases of my graduate program are expressed to Dr. John A. Boezi. His insistance on clarity a and simplicity in the design of experiments and in writing has been a great help to me. My thanks also go to Dr. Harold L. Sadoff whose efforts through the Department of Microbiology and Public Health enabled me to continue the research program with Dr. Boezi. Sincere appreciation is also expressed to the other members of my Ph.D. guidance committee, Dr. Philipp Gerhardt, Dr. Ralph N. Costilow, and Dr. Robert R. Brubaker. I thank the other members of the Biochemistry and Micro- biology and Public Health Departments with whom I have been associated for advice and discussions. Thanks are given to Gary Gerard, Bob Blakesley, Howard Towle, Kathy Rose, and Drs. Lucy Lee, Robert Armstrong, Ken Payne, and Seizen Toyama for discussions. I am indebted to Mrs. Monique DeBacker for technical assistance. I thank the Departments of Biochemistry and Micro- biology and Public Health and the National Science Foundation and the National Institutes of Health for financial support. iii I especially thank the Department of Microbiology and Public Health for presenting a Graduate Office Scholarship to me in the spring of 1969. iv ‘I-hjl" 'v CURRICULUM VITAE OF JAMES CARL JOHNSON May 1, 1971 Biographical Sketch Name: James Carl Johnson Born: October 2, 1942 in Madison, Wisconsin Citizenship: United States of America Marital Status: Married Education (1947-1959) Elementary and Secondary Education--pub1ic schools in Madison, WisconSIh and Waterloo, Iowa. Participant in Northeast Iowa Science Fairs (1957, 1958, 1959). (1960-1964) Undergraduate Education--Iowa State University, Ames, Iowa. Ma'or: Biochemistry National Science Foundation Undergraduate Program participant (1961, 1962, 1963). Title of Project: Purification and Physical Characterization of Feather Keratin. Academic and Thesis Advisor: Dr. Malcolm Rougvie. Graduation Date: May, 1964. (1964-1967) Graduate Educatigf—Department of Biochemistry, East Lansing, Michigan State University, Michigan. Master of Science Thesis Title: Purifica- tion an C aracterization of DNA- dependent RNA Polymerase from Pseudomonas putida A. 3.12. . Thesis Advisor: Dr. John A. Boezi. Stipend: National Institutes of Health Training Grant. (1967-1971) Graduate Education--Department of Micro- bioIbgy and Public Health, Michigan State University, East Lansing, Michigan. Doctoral Thesis Title: DNA-dependent RNA Polymerase of Pseudomonas putida: Purification and Characterization. Thesis and Academic Advisors: Dr. John A., Boezi and Dr. Harold Sadoff. Stipend: N.I.H. Teaching Grant (1969) Received a Graduate Office Scholarship from the Department of Microbiology and Public Health. Publications and Abstracts 1. Boezi, J. A., L. F. Lee, and J. C. Johnson, "Characterization of Bacteriophage gh-l of Pseudomonas fluorescens A 312," Bacteriological Proceedings, 66, No. V27, 113 (1966). 2. Johnson, J. C., and J. A. Boezi, "RNA Polymerase of Pseudomonas putida," Bacteriological Pro- ceedings, 68, No. P115, 131 (1968). 3.1 Johnson, J. C., M. Shanoff, S. T. Bass, J. A. Boezi and R. G. Hansen, "An Enzymic Method for . Determination of Inorganic Pyrophosphate and Its Use as an Assay for RNA Polymerase, Analytical Biochemistry, 26, 137 (1968). ’ " Polymerase 4. Johnson J. C. and J. A. Beri, .RNA from Pseudomonas putida," Federation Abstracts, 891 (1970). . . M. DeBacker, and J. A. Boezi, . J C ' Acid-dependent Ribonucleic ACid domonas putida," Journal of 246 1222 (197II. 5. Johnson, "Deoxyribonucleic Polymerase of Pseu Biological Chemistry; 5. Gerard, G. F., J. C. Johnson, J. A. Boezi, The Release of o from Pseudomonas putida RN: Poly; merase during the DNA-directed RNA Syn e512 9 ' ' ss 1971. Process," Federation Abstracts (in pre ) Egaching Experience ””196” —2r———-———————-£’*De W “first:grasses $3.225. 804 an . Uggéigraduate Laboratory 059 superVised by Dr. E. Benne. . . 400 Honors Laboratory superVised by Dr. F Rottman. vi (1969) Department of Microbiology and Public Health. Microbiology Undergraduate and Graduate Laboratory 401 supervised by Dr. Ralph Costilow. vii TABLE OF CONTENTS GENERAL INTRODUCTION LITERATURE SURVEY . . . . . . . . Introduction . . . . . . . . . . The Essential Role of RNA Polymerase in_vivo Bacterial RNA Polymerase Structure . . . . Protein Factors Affecting RNA Synthesis Sigma I I I I I I I I I Psi . . Rho I I I I I I I I I I I I I M-factor . . . . . . . . . . . . References . . . . . . . . . . . . ARTICLE 1 An Enzymic Method for Determination of Inorganic Pyrophosphate and Its Use as an Assay for RNA Polymerase, J. C. Johnson, M. Shanoff, S. T. Bass, J. A. Boezi, and R. G. Hansen, Analytical Biochemistry, ggJ 137 (1968). . ARTICLE 2 Deoxyribonucleic Acid-Dependent Ribonucleic Acid Polymerase of Pseudomonas putida, J. C. Johnson, M. DeBacker, and J. A. Boezi, Journal of Biological Chemistry, 246, 1222 (1971) ARTICLE 3 35 Purification and Properties of S-labeled RNA Polymerase of Pseudomonas putida, J. C. Johnson and J. A. Boezi (manuscript in preparation). viii Page 24 30 42 GENERAL INTRODUCTION The model for gene expression, developed nearly fifteen years ago, states that genetic information encoded in DNA in the form of deoxyribonucleotide sequences is transcribed into ribonucleotide sequences of RNA. Trans- scription is the process involving base pairing, whereby the genetic information contained in DNA is used to order a complementary sequence of bases in an RNA chain. Several species of RNA molecules which are transcribed from a DNA template have been described. These Species include messenger RNA, ribosomal RNA, and transfer RNA. Each of these species of RNA is specifically involved in the synthesis of polypeptides. Ribosomal RNA is the structural nucleic acid component of ribosomes. Transfer RNA is the Species of RNA that is able to accept and covalently com- bine with an amino acid and to hydrogen bond with a messenger RNA nucleotide triplet. Only messenger RNA, however, carries the information which specifies the Primary structure of polypeptides. Translation of the information encoded in messenger RNA to form the primary structure of polypeptides is the second step in gene exPression. Transcription of DNA is the essential first step in gene function. Considering the importance of gene function in biology, one would like to know the details of control and mechanism of processes required for transcrip- tion. One approach to the study of transcription has been to search for the activities which are required for in yigrg synthesis of RNA from DNA templates in cell-free extracts. This approach was adopted by several laborator- ies nearly ten years ago and led to the discovery of an activity which catalyzed the synthesis of RNA from a DNA template. The enzyme that catalyzes transcription of DNA is RNA polymerase. It was first isolated from bacterial extracts but has recently been isolated from extracts of a variety of prokaryotic and eukaryotic cells. Genetic experiments have been used to demonstrate that the RNA polymerase prepared from bacteria is the major, if not the only, enzymatic activity responsible for the synthesis of messenger, ribosomal, and transfer RNA. Recently, an effort has been directed toward the determination of the subunit polypeptide structure of the purified enzyme. This approach has led to the discovery of protein factors which have the property of influencing the enzyme-mediated reaction in vitro. Until now these studies have been generally restricted to the RNA polymerase obtained from the extensively studied bacterium, Escherchia_coli. Two varieties of RNA polymerase have been prepared from E. coli .‘IV- ‘. yin- nun Vito. .IV 'lI It! . \' q NJ: '\) (f These varieties differed in structure by a single polypep- tide chain, which was called sigma. Sigma was found to cause the RNA polymerase molecule to initiate synthesis at correct sites on the DNA templates used for i§_yit£g synthesis of RNA. When work was begun for this thesis, only a partial purification of the enzyme from E. ggli_had been reported. It was decided that a second example of RNA polymerase from bacterial sources should be provided for study. Pseudomonas putida was utilized as the bacteria from which RNA polymerase was purified beCause the bacteria was being used in related studies of RNA structure and methylation. In addition, a bacteriophage which was specific for P, putida was isolated. It was of interest to determine whether the host RNA polymerase would transcribe the bac- teriophage DNA. The procedure described herein for the purification of RNA polymerase resulted in two forms of the enzyme which were nearly homogeneous. One of the forms contained 100 per cent of the amount of sigma capable of being associated with the enzyme. The other form of RNA polymerase was completely devoid of sigma. This thesis is organized into four major sections. The first is a literature review in which much of the information on bacterial RNA polymerase structure and factors has been described. The second and third sections are composed of articles describing the assay, purification IIP a nut“ t‘fl .qu par . a “A. I II! p win a ,, Dun cub ' '1‘ l and structure of the enzyme. These articles have been included in the form of reprints from the journals in which they were published. The fourth section consists of a manuscript which is to be published. It concerns the puri- fication and properties of 3SS-1abe1ed RNA polymerase from P, putida and the use of the radioaCtive enzyme to inves- tigate the release of sigma factor following the initia- tion of RNA synthesis. “(My F“. o 0‘. 6‘H be m- it 0 LITERATURE SURVEY Introduction The first reports of the detection, isolation, and purification of a DNA-dependent RNA polymerase from bac- terial sources occurred in the early 1960's (1,2,3,4,5). As of now, a prodigious literature concerning bacterial RNA polymerase has accumulated. The extent and variety of topics treated in the literature are beyond the scope of this survey. The following reviews and symposia should be consulted for a comprehensive treatment of the literature (6,7,8,9,10,11). RNA polymerase has been purified from the following bacterial sources: Escherchia coli (several strains) (1,2,5,12,13,14); Azotobacter vinelandii (3,15); Micrococcus luteus formerly Micrococcus lysodeiktus (4); Bacillus subtilis (16); and Pseudomonas indpgophera (17). The most extensively purified enzymes, those obtained from the various strains of E. ggli and the RNA polymerase from A. vinelandii, are homogeneous as determined from sedimen- tation and electrophoretic studies. E. 391$ RNA polymerase has been the subject of most of the kinetic and structural studies. [v 1:. (I. N!- - ob“ put 6.. up! We» 'Pl HI. ll) (I) (I) V: 6 The Essential Role of RNA Polymerase in Vivo Evidence for the role of DNA-dependent RNA polymer- ase was provided through a study of E. coli mutants having alterations in a structural gene(s) for RNA polymerase which rendered the cell temperature sensitive or resistant to the rifamycin antibiotics. A mutant of E, 92;; which rendered the cell temperature sensitive (growth at 30° but not at 42°) was unable to incorporate labeled uridine into RNA at the non-permissive temperature (18). RNA polymerase isolated from the mutant grown at 30° was active when tested Ea IiEEE at 30°, but was considerably less active relative to the wild type RNA polymerase when tested EE_yEE£g_at 42°. Sub— sequent analysis indicated that the E, ggEE_mutant had a structurally altered RNA polymerase molecule. The nature of the alteration has not been determined. Rifamycin or its derivative rifampicin when added to a growing culture of E, ggli_inhibited growth (19,20,21). Wild type E, ggl£_cells were not able to incorporate labeled uridine into RNA following addition of rifampicin to the culture. It was shown that rifampicin inhibited the DNA- directed synthesis of RNA by RNA polymerase E3 yi££9_(22,23). Other studies determined that rifamPiCin binds to RNA poly- merase and blocks initiation of RNA synthesis (24,25). Rifam- picin resistant mutants of E, ggii_have been isolated which synthesize an altered RNA polymerase molecule (21). Rifam_ picin did not bind to the altered enzyme. Consequently, the antibiotic did not inhibit RNA synthesis i2.2££2,°r i2 vitro. The studies on temperature sensitive and rifamycin resistant mutants together with the extensive biochemical studies on the RNA polymerase lead to the conclusion that the RNA polymerase as isolated by the various purification procedures is the "genetic transcriptase" (26), that is, the essential enzyme responsible for most if not all RNA synthesis from a DNA template in the bacterial cell. Bacterial RNA Polymerase Structure The subunit structure of purified E, 99EE_RNA polymerase has been investigated. SDS or urea polyacryla- mide gel electrophoresis of RNA polymerase which was denatured by means of SDS or urea in the presence of reducing agents resolved either three or four polypeptide subunits (27,28). The RNA polymerase which had been chromatographed on phosphocellulose contained three poly- peptide subunits designated 8', B, and a, with molecular weights 165,000, 155,000, and 39,000 respectively. The RNA polymerase which was not purified by phosphocellulose chromatography contained 8', B, a, and o polypeptide sub- units. Sigma (0) has a molecular weight of 95,000 (28). The molar ratio of the polypeptides obtained from the phosphocellulose purified enzyme was 18' : 18 : 2a. The minimal polypeptide subunit formula for this enzyme was “288'. The RNA polymerase which was purified by gel filtration and sucrose or glycerol gradient centrifugation, but not by phosphocellulose chromatography contained 8', 8, a, and o in a molar ratio of 18' : 18 : 2a : lo. The.minimal subunit formula for this enzyme was azBB'o. The minimal formula weights calculated for a288' and 0288'0 5 and 4.93 X 105 respectively. These minimal were 3.98 X 10 fOrmula weights correspond to the monomeric forms of the enzyme. In addition to the 8', 8, o, and a polypeptide subunits of o288' and a288'o, a polypeptide (omega, w) of molecular weight 9,000 was variably associated with the purified enzyme (13,29). It is not known whether w is a structural component of the enzyme or whether it has any function in RNA synthesis. Sephadex G-200 chromatography of denatured a288' in the presence of SDS or urea resulted in the separation of 8 plus 8' from a (27). The 8 plus 8' polypeptide sub- units were separated on DEAE-cellulose in urea (27). The molecular weights of the 8 plus 8' and the a subunits determined by SDS-polyacrylamide gel electrophoresis were found to be the same as those determined by sedimentation equilibrium studies with the isolated subunits. Amino acid compositions of a and of 8 plus 8' as well as the a288' enzyme have been performed (27). Methio- nine is the only N-terminal amino acid of either a, 8, or 8'. Prior to the establishment of the polypeptide sub- unit structure of RNA polymerase, studies of the sedimen- tation properties of the enzyme were confusing. Two, oflVeé pl- .peo ..~u - I “p (v «'9. 0 (fi O‘Oi . I"; Ali-v. 9A,. bvi. 3‘ I.” (I. ‘1- ' 1 HI ‘1; ’I’ three, or more species of molecules were observed in sedi- mentation velocity experiments with highly purified RNA polymerase (30,31). A partial understanding of the effects of ionic strength, subunit composition, preferential hydration, and irreversible dissociation has helped to clarify much of the confusion. Berg and Chamberlin ana- lyzed the two species of RNA polymerase, o288' and a288'o, by sedimentation velocity and equilibrium experiments (29). Apoenzyme (o288') in buffers of ionic strength above 0.26 0 20,w dependence of sedimentation coefficient on the protein behaved as a single sedimenting species (S =12.6). The concentration was slight. When apoenzyme was centrifuged in buffers with ionic strength below 0.26, a variety of aggregated species was observed with average sedimentation coefficients of 44 to 48 S. Holoenzyme (o288'o) in buffers with ionic strength of 0.12 or higher sedimented as a 0 20,w in low ionic strength buffers, the holoenzyme aggregated 0 20,w a full complement of o sedimented as a mixture of apo- and single species with S =15.0. When o288'o was sedimented to a dimer with S =23.0. RNA polymerase with less than holoenzyme at both low and high ionic strengths. The molecular weights determined by sedimentation velocity analysis were in agreement with those calculated from SDS- Polyacrylwmide gel electrOphoresis studies. Molecular weight determinations of 0288' and 0238'0 by sedimentation equilibrium.have not been definitive. IGH ...~ . pA" Vv‘ RA. is. on .1 N. '1! 10 Sedimentation of E, SQli.RNA polymerase in increas- ing concentrations of urea indicated that the 3288' form could undergo large conformational changes or could dis- sociate into smaller species (32). RNA polymerase dis- sociates into its polypeptide subunits in high urea concentrations (27,33). The 9 S species derived from RNA polymerase in low urea concentrations may represent a mixture of a8 and a8' (32). Renaturation of urea or lithium chloride dissociated enzyme to obtain a partially active enzyme which has the characteristics of the non- dissociated enzyme has been described (34,35). The polypeptide subunit structure of the E, vinelandii and the E, subtilis RNA polymerase was found to be similar to the E, coli polymerase. The E, vinelandii RNA polymerase consists of an apoenzyme with polypeptide subunit formula o288' and a holoenzyme a288'o (36). The molecular weights of a, B, 8', and 0 were virtually iden- tical to those from E, EEli.RNA polymerase. E, subtilis RNA polymerase, although not totally purified, contained Pelypeptide subunits of molecular weight 155,000, 120,000 57,000 and 45,000 (37). Two polypeptides at molecular weight 155,000 were resolved. The molar ratio of the 155,000 dalton material to the 45,000 dalton material was 1:1. Chromatography of the enzyme on phOSphocellulose removed the 57,000 dalton polypeptide from the enzyme and resulted in an enzyme activity with altered template 11 specificities. The 57,000 dalton polypeptide is therefore similar to E, ggii_RNA polymerase a factor in function but not in size. Infection of E, EQli.bY T4 bacteriophage results in modification of the host RNA polymerase subunit struc- ture. The a polypeptide chains are modified apparently by the addition of 5' AMP in a T4 phage-specific reaction (38,39). This modification occurs early in infection. Adenylation of RNA polymerase from E, ggl£_by ATP with an activity from uninfected cells has also been reported (40). The adenylated enzyme is less active in RNA synthesis than is the non-adenylated form. Both the 8 and 8' polypeptides are modified late in T infection (39,41). The host 0 4 subunit is replaced by a T -specific 0 factor early in 4 infection (42,43). The T -specific 0 has the same molec- 4 ular weight as the host 0, and it confers different tem- plate specificities to the apoenzyme. Late in T4 infection this T4-specific 0 may be replaced by yet a different T4- specific 0 (41). Infection of E. ggli_with bacteriophage T7 results in the Q2 ERIE synthesis of an entirely new type of RNA polymerase molecule (44). The T7-specific RNA polymerase is a product of gene 1 and is distinct from the host poly- merase in that its activity is not inhibited by rifamycin, streptolydigin, or by antibody specific for the host enzyme. The enzyme consists of a single polypeptide I_-—-_—v-‘r.4 ,V"... .. ' .' 12 subunit of molecular weight 110,000 as determined by SDS- polyacrylamide gel electrophoresis. Structural alteration of E. subtilis RNA polymerase during sporulation has been reported (37). The sporula- tion RNA polymerase has a polypeptide of 110,000 daltons which is not found in the enzyme from vegetative cells. The sporulation enzyme was found to contain only one of the 155,000 dalton polypeptides found in the vegetative RNA polymerase. Protein Factors Affecting RNA Synthesis A series of sequential reactions serve to describe the steps in RNA synthesis by RNA polymerase from a DNA template. These steps in RNA synthesis are association, initiation, elongation, termination, and dissociation. During association, the RNA polymerase molecule interacts with and binds to sites on the DNA template. Initiation occurs with the formation of the first phosphodiester bond between the 5'-termina1 and the second ribonucleotide. Elongation follows with the sequential addition of ribo- nucleoside monophosphates and the release of pyrophosphate. At termination the synthesis of RNA ceases. Dissociation follows termination with the release of the RNA product and the RNA polymerase from the DNA template. Sigga Several proteins have been discovered which have the property of affecting one or more of the steps in RNA 13 synthesis by bacterial RNA polymerase Eg'yiggg. One such protein is the sigma (a) polypeptide subunit of E. 32;; RNA polymerase (28). The E, ggli_sigma subunit has been isolated from holoenzyme (a288'o) by chromatography on phosphocellulose (28). The efficiency by which a DNA template may be transcribed by RNA polymerase is affected by the presence or absence of o. The efficiency by which RNA polymerase transcribes a particular DNA template £2.XiE£2 is measured from the overall rate of RNA synthesis which reflects the rate limiting step in either association, initiation, elongation, termination or dissociation. The initiation reaction may be followed by means of the exchange reaction which occurs between inorganic pyrophosphate and the ribo- nucleoside triphosphates involved in initiation (45). Measurements of RNA synthesis and the pyrophOSphate exchange reaction showed that transcription from E, ggli bacteriophage T was dependent upon the presence of sigma 4 (46). It was concluded that c was probably necessary for the formation of the first phosphodiester bond catalyzed by RNA polymerase. The asymmetry of RNA synthesis from native DNA is affected by the presence of o in the reaction. RNA syn- thesis $2.!i12 is asymmetric and must initiate and terminate at specific sites on the DNA template. RNA synthesis in vitro using holoenzyme is asymmetric on 14 E, 32;; bacteriophage T7 or A DNA and only the early phage genes are transcribed (6,47). Also, E, ggli_holoenzyme catalyzes asymmetric transcription of DNA from E. subtilis bacteriophage SP01 (48), and animal viruses SV40 and adeno- virus (49,50). In contrast, E, gg£i_apoenzyme catalyzes symmetric transcription from a variety of templates (T4, F1, and T bacteriophage DNA) (47,51,52). RNA synthesis 7 by apoenzyme is initiated at non-specific sites on the DNA molecules. Therefore, it may be concluded that o affects a specific interaction between the enzyme and functional sites on the DNA. The nature of the functional sites which specify holoenzyme recognition may be the same or similar on a variety of DNA molecules from different sources. The functional sites for holoenzyme initiation may be equivalent to the promotor regions (53). Thus, sigma may direct the initiation of specific RNA chains by identifying specific DNA promotor regions to which the enzyme may bind. The effect of c on the binding of RNA polymerase to DNA has been studied by a nitrocellulose filter binding assay (54,55). It was found that 0 was not required for formation of an RNA-polymerase-DNA complex. The stability 0f the complex was greatly enhanced, however, by the presence of o. The formation of the DNA-RNA.polymerase holoenzyme complex was temperature sensitive which suggests that a cooperative reaction was involved (39). No more 15 than 7 or 8 molecules of holoenzyme could tightly bind to T7 DNA. These data suggest that o is involved in the formation of a highly stable enzyme-promotor complex which may entail opening of the DNA helix in localized specific regions. 1 From the above studies it may be hypothesized that o is required for recognition of promotor regions on DNA, or o is required for tight binding of the apoenzyme to the DNA, or both. By the first hypothesis, the specific infor- mation for site recognition is located in the 0 subunit. By the second, the site recognition information is located in the apoenzyme. Then, sigma would act as an allosteric effector for tight, site-specific binding. Sigma, in the absence of apoenzyme, will not bind to DNA (55). At some stage of RNA synthesis by E. EQli and E, yinelandii holoenzyme i2 y£E£2_o is apparently released from the enzyme (46,52,56,57). This has led to the postu~ lation of the sigma cycle by Traverse and Burgess (56). The essential feature of the sigma cycle is that once RNA synthesis starts, sigma is released to bind to other apo— enzyme molecules which may subsequently bind to DNA at Specific promotor sites and initiate RNA synthesis. Release of c has not been demonstrated EE_yEyg_and there has been no direct demonstration of the release of o from holoenzyme ig_vitro until now (58 and unpublished obser- vations). The rationale for the release of sigma from holoenzyme during RNA synthesis remains obscure. 16 The incubation of holoenzyme with a variety of ribopolymers in the absence of nucleoside triphosphates results in the apparent release of o (36). This suggests that if c release occurs Eg.yiyg_it may be mediated by RNA. However, much of the RNA synthesized E2_yiyg is bound to either ribosomes in the case of messenger RNA (57) or protein in the case of ribosomal RNA (60) prior to release from the DNA-enzyme-RNA complex and, thus, the RNA may be unavailable for mediation of c release E3 vivo. iii A class of proteins which act as positive control elements in transcription have been isolated. These pro- teins which act as secondary specificity determinants have been named psi (W) (61). One such psi factor which is Specific for the ribosomal RNA genes (Tr) has been parti— ally purified from E, coli (61). In the presence 0f Tr, but not in its absence, E. coli RNA polymerase holoenzyme catalyzes the synthesis of ribosomal RNA 33 vitro using E. coli DNA as the template. The specificity of transcrip- tion by apoenzyme is not affected by Wr- W activity has been found to be associated with r purified QB replicase (61). The RNA replicating enzyme purified from bacteriOphage QB infected E. coli contains a Phagespecific polypeptide chain of 69,000, and three hOSt specific polypeptides of molecular weights 33,000, .-. .l .w Avv‘. u 1" ‘4 ~A 0" )- 17 47,000, and 74,000 (62,63). The Tr activity is associated with the two small host specific polypeptides. Another psi-like factor which has positive control over the lac operon is CAP (64). CAP is a protein which requires bound cyclic AMP for its activity. The cyclic AMP-CAP complex is necessary for the transcription of the 8-ga1actosidase genes by holoenzyme £2 vitro (65). Rho RNA chain termination and release may, in part, be mediated by a protein isolated and extensively purified from E. EQEE_ribosome-free extracts. This protein has been named rho (p) (66). The protein is probably composed of four subunits each with a molecular weight of 50,000 as determined by SDS-polyacrylamide gel electrophoresis and sedimentation velocity experiments. Analysis of the size of RNA transcription products formed by E, gel; holoenzyme using A DNA as the template in the absence of added p determined that most of the RNA products had sedimentation coefficients which were greater than 22 S. In the presence of added p, two classes of RNA having sedimentation coef— ficients of 7 or 12 S were formed. The 7 and 12 S RNA products made Eg.y£E£9 are the same size as the early A- specific messenger RNA made iglyiyg. The 12 8 RNA molecule is probably the messenger RNA of the N gene of A DNA. The Protein product of the N gene is required for transcription of the late 1 genes Ea vitro by E. coli holoenzyme (67). 18 Thus, it has been suggested that the N gene protein is an anti-p factor, a protein which interferes with the activity of p and permits DNA transcription into the late A genes (67,68). M-factor Psi and rho proteins were obtained from the super— natant fraction of E, 22E; cells. Another protein, M- factor, has been purified from the ribosomal fraction of the cell (69). Like sigma, M-factor is a protein which has a sedimentation coefficient of 4 S and increases the rate of RNA synthesis by E, 22l£.RNA polymerase holoenzyme ig_yi££9, Mrfactor binds to purified E. Egli RNA poly- merase holoenzyme. The available data suggest that M- factor participates in RNA synthesis i2.!i££2.b¥ combining with holoenzyme and affecting an event which occurs during or close to initiation (70). 0 Al). f.‘ 10. ll. 12. 13. 14. REFERENCES Chamberlin, M., and Berg, P U.S.A., EE, 81 (1962). ., Proc. Nat. Acad. Sci. Furth, J. J., Hurwitz, J., and Anders, M Chem., 2 7, 2611 (1962). ., J. Biol. Krakow, J. 8., and Ochoa, S., in S. P. Colowick and N. 0. Kaplan (Editors), Methods in Enzymology, Vol. 6, Academic Press, New York, 1963, p. 11. Nakamoto, T., Fox, C. F., and Weiss, S. B., J. Biol. Chem., 239, 167 (1964). Stevens, A., and Henry, J., J. Biol. Chem., 239, 196 (1964). Geiduschek, E. P., and Haselkorn, R., Ann. Rev. Biochem., 8, 647 (1969). Elson, D., Ann. Rev. Biochem., 4, 449 (1965). Yarus, M., Ann. Rev. Biochem., 38, 841 (1969). Geiduschek, E. P., Brody, E. N.. and Wilson. D., Molecular Association in Biology, Academic Press, New York, 1968, p. 163. Lepetit Colloquium on Biology and Medicine, RNA~ polymerase and Transcription, E, American Elsevier PubliShing Company, Inc., New York, 1969. Cold Spring Harbor Symposia on Quantitative Biology, E2, Cold Spring Harbor Laboratory, New York, 1970. Babinet, C., Biochem. Biophys. Res. Commun., EE, 639 (1967). Burgess, R. R., J. Biol. Chem., 244, 6160 (1969). Zillig, W., Zechel, K., Halbwacks, H., Hoppe-Seyler's Z. Physiol. Chem., 351, 221 (1970). , 19 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31,. 20 Lee-Huang, S., and Warner, R. C., J. Biol. Chem., 44, 3793 (1969). Kerjean, P., Marchetti, J., and Szulmajster, J., Bull. Soc. Chim. Biol., 13' 1139 (1967). Tani, T., McFadden, B. A., Homann, R. R., and Shishiyama, J., Biochim. Biophys. Acta., 161, 309 (1968). Igaroski, K., and Yura, T., Biochem. Biophys. Res. Commun., E2, 65 (1969). Wehrli, W., Knfisel, F., and Staehelin, M., Biochem. Bigphys. Res. Commun., 2E, 284 (1968). Hartman, G., Honikel, R. 0., Knfisel, F., Nfiesch, G., Biochim. Biophys. Acta, 145, 843 (1967). Tocchini-Valentini, G. P., Marino, P., and Colvill, A. J., Nature, 220, 275 (1968). Wehrli, W., Nfiesch, J., Knfisel, F., and Staehelin, M., Biochim. Biophys. Acta, 157, 218 (1968). Mizuno, S., Yamazaki, H., Nitta, K., Umezawa, H., Biochem. Biophys. Res. Commun., 29, 379 (1968). DiMauro, E., Snyder, L., Marino, P., Lomberti, A., Coppo, A., and Tocchini-Valentini, G. P., Nature, 222, 553 (1969). Rabussay, D., and Zillig, W., Fed. Exper. Biol. Soc. Letters, E, 104 (1969). Hayashi, M., Hayashi, M. N., and Spiegelman, 8., Proc. Nat. Acad. Sci. U.S.A., 51, 351 (1964). Burgess, R. R., J. Biol. Chem., 244, 6168 (1969). Burgess, R. R., Travers, A. A., Dunn, J. J., and Bautz, E. K. P., Nature, 221, 43 (1969). Berg, D. and Chamberlin, M., Biochemistry, E, 5055 (1970). Richardson, J. P., Proc. Natl. Acad. Sci. U.S.A., E5, 1616 (1966). Smith, D. A., Martinez, A. M., Ratliff, R. L., Williams, D. L., and Hayes, P. N., Biochemistry, E, 3057 (1967). 32. 33. 34I 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 21 Ishihama, A., and Hurwitz, J., Federation Proc., EE, 659 (1969). Walter, G., Seifert, W., and Zillig, W., Biochem. Biophys. Resy_Commun., EE, 240 (1968). Lill, U. I., and Hartmann, G. R., Biochem. Biophyg. Res. Comm., 32, 930 (1970). Sumper, M., Riepertinger, C., and Lynen, F., Fed. Europe. Biochim. Soc. Letters, E, 45 (1969). Krakow, J. S., and Von der Helm, K., Cold Spring EarborlSymposia on Quantitative Biology, E2, 73 (1970). Losick, R., Shorenstein, R. G., and Sonenshein, A. L., Nature, 227, 910 (1970). Goff, C. G., and Weber, K., Cold Spring Harbor Symposia on Quantitative Biology, 3;, 101 (1970). Zillig, W., Zechel, K., Rabussay, D., Schachner, M., Sethi, V. 8., Palm, P., Heil, A., and Seifert, W., Cold Spring Harbor Symposia on Quantitative Biology, 2;, 47 (1970). Chelala, C. A., Hirschbein, L., and Torres, H. N., Proc. Natl. Acad. Sci. U.S.A., fig, 152 (1971). Travers, A., Cold Epring Harbor Symposia on Quanti— tative Biology, EE, 241 (1970). Travers, A., Nature, 223, 1107 (1969). Travers, A., Nature, 225, 1009 (1970). Chamberlin, M., McGrath, J., Waskell, L., Nature, 228, 227 (1970). Krakow, J. S., J. Biol. Chem., 241, 1830 (1966). Dunn, J. J., and Bautz, E. K. F., Biochem. Biophys. Res. Commun., 3;, 925 (1969). Summers, W. C., and Siegel, R. B., Natugg, 223, 1111 (1969). Grau, 0., Ohlsson-Wilhelm, B. M., and Geiduschek, E. P gold Sprin Harbor 8 mposia on Quantitative Biology, 32, 221 (1970). 'I 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 22 Westphal, H., and Kiehn, E. D., Ibid., p. 819. Green, M., Parsons, J. T., Pina, M., Fujinaga, K., Caffier, H., and Londgraf—Leurs, I., Ibid., p. 803. Sugiura, M., Okamato, T., and Takanami, M., Nature, 225, 598 (1970). Bautz, E. K. F., Bautz, F. A., and Dunn, J. J., 'Nature, 223, 1022 (1969). Arditti, R. R., Scaife, J. G., Beckwith, J. R., J. Mol. Biol., _E, 421 (1969). Jones, 0. W., and Berg, P., J. Mol. Biol., EE, 199 (1966). Hinkle, D. C., and Chamberlin, M., Cold Spring Harbor Symposia on Quantitative Biology, E2, 65 (1970). Travers, A. A., and Burgess, R. R., Nature, 22 , 537 (1969). Darlix, J. L., Sentenac, A., Ruet, A., and Fromageot, P., Europe. J. Biochem., ii, 43 (1969). Gerard, G. F., Johnson, J. C., and Boezi, J. A., Fed. Proceedings, 1971 (in press). Miller, 0. L., Beatty, B., Hamkalo, B., and Thomas, C. A., Cold Spring Harbor Symposia on Quantitative Biology, EE, 505 (1970). Mangiarotti, G., Apririon, D., Schlessinger, D., and Silengo, L., Biochemistry, Z, 456 (1968). Travers, A. A., Kamen, R. I., Schleif, R. F., Nature, 228, 748 (1970). Kamen, R., Nature, 228, 527 (1970). Kondo, M., Galleroni, R., and Weissmann, C., Nature, 228, 525 (1970). Zubay, G., Schwartz, D., and Beckwith, J., Proc. Natl. Acad. Sci. U.S.A., EE, 104 (1970). Eron, L., Arditti, R., Zubay, G., Connaway, S., and Beckwith, J. R., Proc. Natl. Acad. Sci. U.S.A., _6_8_, 215 (1971) . Roberts, J., Nature, 224, 1168 (1969). 67. 68. 69. 70. 23 Roberts, J., Cold Sprin Harbor S m osia on Quantita- tive Biology, EE, lgI (I970). Schwartz, M., Virology, 32, 23 (1970). Davidson, J., Pilarski, L. M., and Echols, H., Proc. Natl. Acad. Sci. U.S.A., E3, 168 (1969). Davidson, J., Brookman, R., Pilarski, L., and Echols, H., Cold Spring Harbor Symposia on Quantitative Biology, EE, 95 (1970): ARTICLE 1 AN ENZYMIC METHOD FOR DETERMINATION OF INORGANIC PYROPHOSPHATE AND ITS USE AS AN ASSAY FOR RNA POLYMERASE BY J. C. Johnson, M. Shanoff, S. T. Bass, J. A. Boezi, and R. G. Hansen Reprinted from Egalytical BiochemistEy, 26, 137 (1968) 24 .A '1 fl!" . . 431146": ' osphafe and Its Use as an Assay for RNA Polymerase . ‘ :l " IN, MIKE SHANOFF, S. T. BASS, J. A. BOEZI, ‘3 AND R. G. HANSEN -. 0! Biochemistry and Microbiology, Michigan State University, East Lansing, Michigan 48823 Received February 13, 1968 v "'0 pyrophosphate (PP,) is a product of many biosynthetic ;; In biopolymer formation PP, arises (a) in protein synthesis ; lingo of amino acid activation, (b) in nucleic acid synthesis at aversion in the formation of the glycosyl donor, and (d) in lipid ,: at the stage of fatty acid activation. usual method of PP, analysm involves its hydrolysis to inorganic hosphate (P,) followed by P, determination by the Fiske and :i-w method (1). Both inorganic and organic phosphate com- 3v“ n n: interfere in this analysis. ‘iklbrecht, Bass, Seifert, and Hansen (2) reported the purification and ._ * ; ’ation of UDP-glucose pyrophosphorylase from calf liver. The thility of this crystalline enzyme has made possible the develop- M of a specific enzymic method for the determination of PP,. Using ‘_‘.}hsphoglucomutase and glucose-G-phosphate dehydrogenase—both of W are commercially available, and UDP-glucose pyrophosphorylase, m can be quantitatively determined from the amount of NADPH . bread in the following series of reactions: o, Exfozgmrylase PP: + UDP-glucose ——p————' UTP + glucose-LP phosphoglucomutue ‘ , glucose-LP ———————~ gluoose-fi-P ’7 amt... (km? + NADP ————-——-—-+ gluconolactone-G—P + N ADPH . .ble assay conditions, one equivalent of NADPH will be " fi- 'ofPPp -vi.e., coupling the determination of PP, with the forms. 138 JOHNSON, SHANOFF, BASS, BOEZI, AND HANSEN tion of NADPH via the three enzyme-catalyzed reactions, can also he used as an assay for enzymes which generate PP, as a reaction product. A description of the enzymic method for the determination of PP, and the application of the method for the assay of DNA-dependent RNA polymerase is the subject of this report. MATERIALS AND METHODS NADP, UDP-glucose, glucose-6—phosphate dehydrogenase, and the 5’- phosphate derivatives of adenosine, guanosine, uridine, and cytidine were obtained from P-L Biochemicals, Inc. Calf thymus DNA, pancreatic RNase (type I-A) , and phosphoglucomutase were purchased from Sigma Chemical Co. DNase I (electrophoretically purified) and inorganic pyrophosphatasc were obtained from Worthington Biochemical Corp. [‘H]-ATP and [sHl-CTP were purchased from Schwarz BioResearch, Inc. Actinomycin and nogalamycin (3) were gifts from Merck, Sharp, & Dohme, and The Upjohn Company, respectively. UDP-glucose pyrophosphorylase was isolated from calf liver by the procedure of Albrecht, Bass, Seifert, and Hansen (2) and recrystallized twice. RNA polymerase was purified from Pseudomonas putido A312 by a procedure that will be the subject of another communication (4). For the experiments reported here, ammonium sulfate fraction II (A.S.II) of RNA polymerase was used. No inorganic pyrophosphatase activity has been detected in this fraction. Using 100 [Lg/ml P. putida bacte- riophage gh-l DNA as template, A.S.II had a specific activity of 2500— 3000 mnmoles CTP converted into a trichloroacetic acid insoluble form per hour per milligram protein (radioactive assay). In the spectrophotometric assay, A.S.II had a specific activity of 5000—5500 mnmoles NADPH formed per hour per milligram protein. P. putida bacteriophage gh-l DNA (5, 6) was purified by the method described by Thomas and Abelson (7). The concentrations of both dl-I DNA and calf thymus DNA were determined from their ultraviolet ab- sorptions using the extinction coefficient Emil" = 200. Calf thymus DNA was denatured by heating at 100° for 10 min, followed by quick 000131188 For the determination of PP, by the UDP-glucose pyrophosphorylaie assay system, the reaction mixture contained, in 0.5 ml: 50 mole We: acetate buffer (pH 8.0), 1 nmole magnesium acetate, 0.2 mole 0.2 ”mole UDP-glucose, excess phosphoglucomutase and g1 u -..-. 7 phate dehydrogenase, from 5 to 20 mnmoles PP,, and errands glucose pyrophosphorylase so that reaction was complete in " NADPH formation was measured at 340 111,, in a : «hp. 3 equipped With a Gilford BW‘ .3; g; _ .' éaES—s Eu} gar!- ... _ a ‘ 3 mo moo r011 PP, DETERMINATION 139 " '. = using the molar extinction coefficient of 6.22 X 10’ (9) . "' "; mixture employed for the formation of RNA com- “NA by RNA polymerase contained, in 0. 5 ml. 10 moles 7 ; .'.' uer (pH 8.0), 1 mole magnesium acetate, 0.25 mole V' “site, 0.2 mole each of ATP, GTP, CTP, and UTP, 0.1 ', 0.1 mole UDP-glucose, excess phosphoglucomutase, hate dehydrogenase, and UDP- glucose pyrophosphoryl- a u 1 DNA, and 4 to 17 ,ug RNA polymerase. Before initiating : .. with RNA polymerase, a 20 min incubation was required ’, reaction of PP, contaminating the nucleoside triphosphates. formation was measured at 340 my in the spectrophotometric ‘ the radioactive assay, [3H] -CTP (5 X 108 cpm/nmole)o (3 X 10‘ cpm/nmole) was used. Material, insoluble in 10% *I v I cetic acid, was collected on nitrocellulose membrane filters ' ed for radioactivity in a liquid scintillation spectrometer. l'eaction mixture for polyriboadenylate (poly A) synthesis by 7., . 1 nerase contained, in 0. 5 ml: 10 nmoles Tris acetate (pH 8 0), magnesium acetate, 0.25 nmole manganese acetate, 0.2 mole ,1le mole NADP, 0.1 nmole UDP-glucose, excess phosphoglu- j. , glucose-6-phosphate dehydrogenase, and UDP- glucose pyro- ' lacs, 50 pg heat-denatured calf thymus DNA, and 70 pg RNA = w For the radioactive assay, [3H]-ATP (1 X 101 cpm/gmole) RESULTS .1. {nation of Inorganic Pyrophosphate by the Pyrophosphorylase System. The results presented in Table 1 demonstrate the equiv- - 1 . between PP, added to the pyrophosphorylase assay system and L 'r‘ 7,; H formed. For the three experiments reported, using from 5 to i ’ -~‘_r «I‘Iles of PP, per assay mixture, an equivalent amount of NADPH armed. An equivalence between .PP, and NADPH was also found TP,," 5'-mono-, di-, or triphosphate derivatives of adenosine or 31 ., a mixture of the four nucleoside triphosphates, RNA polymerase, TABLE 1 .... tion of Inorganic Pyrophosphate by Pyrophosphorylase Assay System PP: added. mole- NADPH formed, moles Expt. 1! Expt. [[1 Exm. I Expt. II Expt. 1n 5.2 5.6 4.9 5.0 5_3 10.0 10.0 10.1 10.0 10.4 .0 15.1 14.8 15.2 16.0 .0 20.2 19.5 21.1 20_o JOHNSON, sumo”, BASS, BOEZI, AND HANSEN TABLE 2 Efiect of Various Agents on Determination of Inorganic Pymphouphatl Additions to pyrophosphorylase NADPH. assay system mole- 15 mumoles PP, 15.0—15.5 +150 mnmoles P, 15.5 +15,000 mpmoles P, 14.8 +200 mpmoles AMP 15.0 +200 mumoles ADP 16.2 +200 mnmoles ATP 15.9 +200 mpmoles UMP 14.5 +200 mpmoles UDP 15.3 +200 mumoles UTP 14.5 +200 mpmoles each of ATP, GTP, UTP, and CTP 14.6 +35 ug RNA polymerase 10.1 +250 ug denatured calf thymus DNA 16,1 or denatured calf thymus DNA were added to the assay mixture (Table 2). In other experiments, it was shown that actinomycin or nogalamycin do not interfere in PP, determination. Spectrophotometric Assay for RNA Polymerase. The requirements for the reduction of NADP by the pyrophosphorylase assay system can- comitant with the generation of PP, by RNA polymerase were detarv mined. The results are given in Tables 3 and 4. If RNA polymerase, gh-l DNA, the four nucleoside triphosphates, the purine nucleoside triphos- phates, or the pyrimidine nucleoside triphosphates were omitted from the reaction mixture, no NADPH was formed (Table 3). As shown in Table 4, when DNase, inorganic pyrophosphatase, actinomycin or nogalamycin was added to the reaction mixture, little or no NADPH ml formed. However, when RNase was added to the reaction mixture, the formation of NADPH was stimulated. The stimulatory efiect of RNase . on PP, formation by RNA polymerase has been reported by Krakoi (10) and Maitra and Hurwitz (11). In Figure 1 the relationship between the rate of NADPH format!” TABLE 3 " Requirements for NADPH Formation Concomitant with Synthesis of REA: ’ ‘ Compomuol "’ motion mixture NADPH. mole/min/ml .00 ‘ 1 men 103 PP, DWINATION TABLE 4 of Various Agents on NADPH Formation .‘ Concomitant with Synthesis of RNA . . . . N ADPH. mumolee/min/Inl O 3; i 5' E cook-o.— asses cl van t of added RNA polymerase is given. Under the assay employed, the relationship was linear to the formation of 2 NADPH/min/ml. 1 amount of RNA synthesized is proportional to the amount polymerase used (12, 13). Likewise, the total amount of formed was proportional to the amount of RNA polymerase the assay system. For example, when 8.5, 17, 25.5, and 34 ug/ml ;~ .1; ::e were used, 19, 34, 50, and 64 mpmoles/ml NADPH ‘7 ..,~. - , respectively. kinetics of NADPH formation as measured in the spectrophoto- .leeay and RNA synthesis as measured by the conversion of [3H] Md ['H]-ATP into a trichloroacetic acid insoluble form are given - 2. Following a short lag, the rate of NADPH formation was , l‘es/min/ml. The rates of incorporation of UMP and AMP were I ' ' _‘ 5 0.0 mpmoles/min/ml, respectively. At the plateau, approximately . } lee/ml of NADPH was present, and 16 and 9 mamoles/ml of . and AMP had been incorporated into RNA. - aft“ ‘6' I !° 0 1 b NADPH (mpmoles/min/ml) . 1 IO 20 30 RNA POLYMERASE (Mg/ml) ~ '1' between rate of NADPH formation and mount of 11m 142 JOHNSON, SHANOFF, BASS, BOEZI, AND HANSEN For comparison of the results of the two assay procedures, it should- 1 pointed out that the spectrophotometric assay measures the formation of NADPH as a consequence of the production of PP, by RNA polymers- ase. PP, is generated by RNA polymerase concomitant with the 111-» corporation of each of the four nucleotides into the intrachain phoepho: diester link of RNA. No distinction is made between the synthesis of trichloroacetic acid soluble or insoluble polyribonucleotides. The radio active assay measures the incorporation of one of the four nucleotidm into polynucleotides which are insoluble in trichloroacetic acid. syn- thesis of oligo- or polynucleotides which are soluble in trichloroacetic acid is not detected. sszaaiefii O. 2 NADPH < so - f 3:: . m E 2 8 o '5 4O - E L o :1. I .5, o_ _ CMP 9, 2° Men»: ..... - 2 017 ..-_._.§C—.————O- 1 1 1 1 20 4O 60 80 TIME, in minutes FIG. 2. Time course of NADPH formation and CMP and AMP incorporation into RNA. The base composition of the RNA product has not been determined and is not necessarily identical to that of gh-l DNA (mole % G + C = 57.0) which served as template (5). However, if it is assumed that the base composition of RNA is the same as the gh- 1 DNA template, the total nucleotides incorporated into the TCA insoluble RNA product may be calculated from the amount of CMP and AMP incorporated. ‘ amounts to 56 mpmoles/ml from the CMP data and 41 m ... ‘ from the AMP data. The former estimate is in good agreement; the is somewhat lower than the amount of NADPH found in the :‘a . , tometrie assay. However, the fact that the estimate of " nucleotides incorporated into RNA 1s difierent when cal . ‘ if“!!! moo ma PP, DETERMINATION 143 tion concomitant with the generation of PP. during u 'b'oadenylate (poly A). The kinetics of NADPH l-AMP incorporation into poly A are presented in . : rates of NADPH formation and AMP incorporation - 'r, somewhat more NADPH was present near the end indicating the synthesis of some trichloroacetic acid i 01' the incorporation of UTP, produced in the UDP- ... .horylase reaction, into polymer. No NADPH was RNA p01ymerase was omitted from the reaction mixture or , .-.. calf thymus DNA was used in place of heat-denatured 51 DNA. 2 I00 - NADPH E \ n 2 2 so ' AMP "_o e ,A/ v ’1’ O 0. __ I 2 60 / < 5 I 40 - (L O ‘2‘ o 20 - I NADPH (minus RNA polymerase I, or with unheated I calf thymus DNA) I _4—.- so 120 130 TIME, in minutes . . DISCUSSION ”amation of PP, via the action of UDP-glucose pyrophos- "" PhOSPhOglucomutase, and glucose-6-phosphate dehydrogenase ' "' to be accurate, sensitive, and specific. The method is limited the sensitivity of the quantitative determination of NADPn " Ipecificity of the enzymes. Neither P. nor any of the organic Compounds tested interfered with PP, determination. 3 Hinalietho'd for measuring PP; has been adapted for use as ;wm polymerase. Using this method, the formation of r“ 4.. ‘ "1' k A. .‘I ' ' k 1 \ .L.‘ 7 O 4 0 ,V‘ 144 JOHNSON, SHANOFF‘, 111133, 301121, AND HANan NADPH—as a consequence of the generation of PP, by RNA polymefi ase—can be easily measured at a rate of 0.1—0.2 mnmole/Inin/ml. M thermore, the enzymic assay procedure permits a continuous monitoring- In of the RNA polymerase reaction. Consequently, a study of the ‘- -'«1, ' kinetics under a variety of conditions can be conveniently performedli‘ addition to these attributes, the spectrophotometric assay has certain advantages over the radioactive assay. The amount of NADPH formed is a direct measure of the total nucleotides incorporated into the intra- chain phosphodiester link of the polyribonucleotide product. In the I“, radioactive assay, a knowledge of the base composition of the productis required in order to calculate the amount of polymer formed from the incorporation of one nucleotide. Furthermore, the solubility of the polymer product in trichloroacetic or perchloric acid is not a factor inthe spectrophotometric assay as it is in the radioactive assay. . The enzymic method for the determination of PP, should find applica- I,“ tion for the assay of many enzymes which generate PP, as a reaction 1 product. Some examples are DNA polymerase (14), RNA-dependent RNA polymerase (15) polyriboadenylate polymerase (16), the amino- acyl-sRNA synthetases (17), and the fatty acid activating enzymes (18). Although PP, is a product of many biosynthetic processes, the intra- on cellular concentration of PP, is low due, supposedly, to the action of I“ ubiquitous inorganic pyrophosphatases (19). The hydrolysis of PP, may - be considered to be an energetically wasteful process since the energy of the anhydride bond is lost as heat. However, in the phosphorylation of glucose in liver microsomes (20) and in the formation of phase phoenolpyruvate in the propionic acid bacteria (21) PP, serves as on energy source. Futhermore, PP, has been implicated in photophos- phorylation in Rhodospirillum rume (22) and in oxidative phos- phorylation in Acetobacter suboxydans (23) and in Escherichia (24). Knowledge of the intracellular levels of PP, in a variety of arm- nisms might provide a clue to the metabolic fate of PP,. Methods have not been available that are sufficiently sensitive or specific for the termination of PP, in biological material. The use of this present : _ cedure, which is limited only by the sensitivity of the quanti " determination of NADPH and by the specificity of the enzymes,- 1 ll help clarify the function of PP, in metabolism. IIIIFFsEEEcF! Fra- SUMMARY 1. An ensymic method for the determination of PP, has _ god. PP, can be quantitatively estimated from the ‘ the action of EDP-glucose 1 ‘4 -,-' an. ' ‘30 men FOR PP, DETERMINATION $11 phosphate compounds tested interfered in the PP, {has been used for the assay of DNA-dependent RNA coupling the generation of PP, by RNA polymerase .1 Ormation. The RNA polymerase catalyzed syntheses of g A . 'boadenylate have been assayed by this procedure. . “ ‘ ACKNOWLEDGMENTS . ' . 1 1‘ ‘ ‘.' . ‘ 7 e- ,. ,1 ." l” technical assistance of Madame M. DeBacker is acknowledged. ff," V .M by National Institutes of Health Grant AM 11156. Michigan . _ T.) ‘ ‘ 1.; rinlent Station Journal No. 4289. . _. 5'1. W _ REFERENCES 5- ‘1 - ‘, H., AND Swallow, Y., J. Biol. Chem. 66, 375 (1925). ‘ .. , G. J., Base, S. T., Smear, L. L., AND HANSEN, R. G., J. Biol. Chem. ‘ 1: 3 (1966). , r , B. K., am: sum, 0. G., Proc. Natl. Acad. Sci. Us. 54, 566 (1965). - 1 -‘ »’. ~' :31 C-o AND Bow, J. A., manuscript in preparation. 1t. m Bow, .1. A., J. Bacterial. 92, 1821 (1966). 1 _ .. 1’1. m Bow, J. A., J. Virology 1, 1274 (1967). . , 1» C. A., AND ABELSON, J ., in “Procedures in Nucleic Acid Research" (8. 1. 1'1 and David R. Davies, eds.), p. 553. Harper & Row, New York, 19605 . f s" . W. A” AND GILF‘ORD, S. R., Anal. Biochem. 2, 601 (1961). ‘ , .' i ' . A., 111m Hakeem, B. L., Biochem. Prepn. 3, 24 (1953). . - . .; 1 .1. 3, J. Biol. Chem. 241, 1830 (1966). . T‘s? U., AND Huawrrz, J ., J. Biol. Chem. 242, 4897 (1967 ). . 1.1 - H. m Komn, M. W., Proc. Natl. Acad. Sci. U. s. 51, 807 (1954). 1' 2 N. J. P., J. Mol. Biol. 21, 115 (1966). n. A., Science 131, 1503 (1960). I. Am: ammu, 3., Proc. Natl. Acad. Sci. U. s. 54, 579 (1965). 1 J- T., 03112, P. J., m1 Hvawrrz, J., J. Biol. Chem. 237, 3786 (1962). , - E. B., m) zAuscmx, P. C., J. Biol. Chem. 221, 45 (1956). 1 1111,1115 WAKIL, s. J., J. Biol. Chem. 204, 453 (1953). 1 R. C. m» Lam, H. A., Biochim. Biophys. A;‘?195:£)189 (1961). ‘ W. J ., m) Nashua, R. C., J. Biol. Chem. 239, 275 . 1’ H. G., Duns, J. J., AND LocHMiiLLsa, H., J. Biol. Chem. 241, 5692 (1966). "“1“, M., Nature 216, 241 (1967). ‘ ' mn. L., KING, T. E., AND CHELDELIN, _ 11.957). 11.1? 1 ' ~ nan. L., Biochim. Biophys. Am 34, 586 (1959). V. H., J. Biol. Chem. 227, 135 ARTICLE 2 DEOXYRIBONUCLEIC ACID-DEPENDENT RIBONUCLEIC ACID POLYMERASE 0F PSEUDOMONAS PUTIDA BY J. C. Johnson, M. DeBacker, and J. A. Boezi Reprinted from Journal of Biological Chemistry, 216, 1222 (1971) 30 it‘lllt \ . T1111: Jornmn OF BIOLOGICAL CHEMISTRY 1111.246, No. 5, Issue of March 10, pp. 1222—1232, 1971 Printed in U.S.A. Deoxyribonucleic Acid-dependent Ribonucleic Acid Polymerase of Pseudomonas putida* (Received for publication, June 5, 1970) J. C. JOHNSON, M. DEBACKER, AND J. A. BOEZI From the Departments of Biochemistry and of Microbiology and Public Health, Michigan State University, East Lansing, M ichigan 48823 SUMMARY Two forms of RNA polymerase (nucleoside triphosphate- RNA nucleotidyltransferase, EC 2.7.7.6) from Pseudomonas putida were resolved by chromatography in 50% glycerol on phosphocellulose and purified. As determined by sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis, the subunit structures of the two forms of the enzyme were aside and agfifi’. The molecular weights of a, B, B’, and a were 44.000, 155,000, 165,000, and 98,000, respectively. The sedimentation coeflicients of azfifi’a and 0121313" as determined by sucrose gradient centrifugation in 0.40 M potassium acetate were 13 S and 12 S, respectively, but in 0.05 M potassium ace- tate, the sedimentation coefficients were 19 S and 25 S. Similar results were Obtained by analytical ultracentrifuga- tion. Multiple protein bands resulted from polyacrylamide disc gel electrophoresis of 0263'0' and azBB’. Each band was enzymatically active in the unprimed synthesis of poly A 1p01y U. RNA polymerase azfifi'a was 4- to 5-fold more active in transcribing P. putida bacteriophage gh-l DNA and coliphage T1 DNA than was (1.1352 With calf thymus DNA as a tem- Plate. the two forms were equally active in RNA synthesis. With denatured DNA or poly d(A-T), a236’ was twice as active as was azBB’a. The rates of the DNA-directed polym- erization reactions catalyzed by agfifi’a and agfifi' were 81' fected difierently by added RNase. The initial rate of the reaction catalyzed by azfifi’a was increased 10%. Whereas that catalyzed by azfifi’ was increased 80 to 110%. DNA-dependent RNA 1.)olymcrasc (ribonucleoside triphos— lete-RNA nucleotidyltransferase, EC 2.7.7-6) has be?“ P11”— ficd and characterized from a number of bacterial sources (1-6). The enzyme from Escherichia coli has been the most extensively studied. It has been purified by a variety of procel'lurcs .(l, 7‘16). and its catalytic and physical moperties have been studied bl‘fl number of laboratories (9, 10, 12, 13, 17—31)- A method utilizing phosphocellulose chromatography for the c This work was supported in part by Grant (iB-‘i’lllkl from the butional Science Foundation. This is blichil-Can Agriculture L)“ Periment Station Article 5112. purification of E. coli RNA polymerase has been described by Burgess (22). The subunit structure of enzyme prepared by this method, designated core enzyme, was azfifi' (23). Burgess, Travers, Dunn, and Bautz (24) showed that a, a subunit which is involved in the initiation of RNA synthesis, was separated from the core enzyme by phosphocellulose chromatography. The subunit structure of the holoenzyme or complete enzyme was agfifi’a. At the present time, only the subunit structure of the E. coli enzyme has been documented in detail. Knowledge of the structural as well as the catalytic properties of RNA polym- erase from other sources must be acquired before a generalized view of structure and function in the transcriptional process can be set forth. This report describes the purification of RNA polymerase from Pseudomonas putida. Two forms of the enzyme have been re- solved by phosphocellulose chromatography. Each form has been characterized with respect to its subunit composition and certain of its physical and catalytic properties. EXPERIMENTAL PROCEDURE .l-Iaterials—«Whatman DEAE-cellulose (DE-1) and phospho- cellulose (P-l) were purchased from Reeve Angel, New York, New York. UDP~glucose, NADP, glucose 6—phosphate dehy- drogcnase, dithiothreitol, and the unlabeled 5’-phosphate de- rivatives of the ribonucleosides were obtained from P-L Bio- chemicals. 3H-Labeled ribonucleotides were from Schwarz BiOResearch. Calf thymus DNA, herring sperm DNA, pan- creatic RNase (type LA), and phosphoglucomutase were from Sigma. Pancreatic DNase I (electrophoretically purified) and catalase were obtained from Worthington. UDP-glucose pyro- phosphorylase was isolated from calf liver (25) and recrystal- lized twice. RNA polymerase from E. coli K—12 was a gift from C. Scharrenberger and E. K. F. Bautz, Rutgers University. Poly d(A-T) was purchased from Miles Laboratories, Inc., Elk- hart, Indiana. Actinomycin D and nogalamycin were gifts from Merck Sharpe and Dohme and The Upjohn Company, respectively. Rifampicin was purchased from Mann. Acryla- mide and bis-acrylamide were from (‘analco, Rockville, Mary- land, and recrystallized according to the procedure of Loening (26). Ethidium bromide and (Toomassie brilliant blue were obtained from Calbiochem and (“olab Laboratories, Inc., Glen- ,mod, Illinois, reSpectively. Diethyloxydiformate was pur- chased from Naftonc, Inc., New York, New York. Nitrocellu- 1222 Issue of March 10, 1971 lose. membrane filters, type B-6, were from Schleicher and Schuell, Inc., Keene, New Hampshire. Growth of P. putida—P. putida (the same or similar to ATCC 12633) was grown in lOO-liter volumes in a New Brunswick Fermacell, model F-130. The growth medium contained the following in grams per liter: yeast extract, 5; glucose, 8; NaCl, 8; (NHJgHPOi, 6; KH2P04, 3; MgSOi-7H20, 1; and FeCl;, 0.005. The cells were grown at 33° with aeration at 8 to 10 cu ft per min into the early stationary phase and then harvested in a Sharples centrifuge. The 1800 to 1900 g (wet weight) of packed cells were stored at -20°. Preparation of DNA and RNA-—P. putida bacteriophage gh-l DNA (27, 28) and E. coli bacteriOphage T4 DNA were purified by the method of Thomas and Abelson (29). (‘alf thymus DNA was further purified by SDsl-phenol extraction. P. putida DNA and E. coli ’H-DNA were prepared by the procedure of Thomas, Berns, and Kelly (30). After RN ase treatment and phenol extraction, the DNA preparation was mixed with diethyloxydi- formats and incubated at 22° for 30 min. Following phenol extraction, ethanol precipitation, and isopropyl alcohol f ractiona- tion, the DNA was dissolved in a butler containing 0.01 M Tris acetate (pH 8.0), and 0.1 M sodium acetate and dialyzed for 10 hours. Denatured DNA was prepared by heating dilute solu- tions of DNA at 100° for 20 min, followed by quick cooling in ice water. E. coli-soluble and ribosomal 3H -R N A were prepared as described by Payne and Boezi (31), Native DNA and RNA concentrations were determined spectrophotometrically based on the extinction coefficient Eti’t = 200. Radioactiw Assay of RNA Polymerase—The radioactive assay of FNA polymerase measured the incorporation of CMP into a form insoluble in trichloracetic acid. The reaction mixture contained 20 mM Tris acetate (pH 8.0), 4 mM magnesium ace— tate, 1 mM manganese acetate, 60 mM ammonium acetate, 0.4 out each of ATP, GTP, (TP, and FTP, and 110 pg per ml of DNA and RNA polymerase. CT P was labeled with 3H at 5 X 103 Chm per nmole. Incubation was at 30° for 10 min unless otherwise indicated. After incubation, 50- to 250p] samples of the reaction mixtures were mixed with 100 pl of 0.1% SDS. (.‘old 10‘}, trichloracetic acid (5 ml), which had been filtered through Celite, and 250 pg of herring sperm DNA were added. After 15 min at 0—4°, insoluble material was collected on a nitro— cellulose membrane filter. The filter was washed with four 5-ml Minions of cold 10% trichloracetic acid, dried, and then moni- tored for radioactivity in a liquid scintillation spectrometer. The scintillation fluid (5 ml) contained 4 g of 2,5 bisl2-(5-tert- l)utyl-henzoxazolyl)]thiophene per liter of toluene. One unit of RNA DOIymerase activity was defined as that amount of enzyme Which catalyzed the incorporation of l nmole of (.‘MP per hour 3t 30°. The specific activity was the number of units per mg of ltmtxein. Protein concentrations were determined by the method of Lowry et al. (32) with bovine serum albumin as a standard. SPeClTOletometric Assay of RNA Polymerase—The spectro- photometric assay of RNA polymerase as described by Johnson ii ‘11- (33) Coupled the formation of inorganic pyrophosphate t0 NADP‘r reduction. In addition to the components used in the r{Idioactive assay, the reaction mixture contained 0.2 mM NADP+, 0.2 mm UDP-glucose, and excess phosphoglucomutase, glucose 6‘DhOSphate dehydrogenase, and UDP~glucose pyrophos— l’hOTYlase. Incubation was at 30°. Calculation of the number 1The abbreviation used is: SDS, sodium dodecyl sulfate. J. C'. Johnson, M. DeBacker, and J. A. Boezi 12233 of nanomoles of NADPH formed was made with the molar extinc- tion coefficient of 6.2 X 10’ (34). Assay of Other Enzyme Activities—The assay for exo- and endo- DNase and RNase measured the solubilization of 3H-l)NA and 3H-soluble RNA and 3H-ribosomal RNA. An additional assay for endonuclease measured the change in sedimentation patterns of ’H-DNA in alkaline sucrose gradients. Inorganic pyrophosphatase was determined by measuring the change in inorganic pyrophosphate by using the coupled UDP-glucose pyrophosphorylase assay system (33). ATP-AMP phospho- transferase was measured by the formation of 3H-ADP from 3H- ATP and AMP. Enzymes which hydrolyze the ribonucleoside triphosphates were measured by the formation of ribonucleoside mono- and diphosphates which were identified by paper chroma- tography in isobutyric acid-NHiOH-HQO (66: l :33). ATP-R NA adenylyltransferase was measured as described by Payne and Boezi (31). (.‘atalase was determined spectrophotometrically by measuring the disappearance of H202 at 240 nm. lil)l-’— glucose pyrophosphorylase was measured as described by Al- brecht et al. (25). Polyacrylamide Disc Gel Electrophoresis—Polyacrylamide gels were prepared according to the general procedures of Davis (35) and Ornstein (36). Clear gels were prepared from a solution which was 3.75% in acrylamide by mixing together 1 part water, —l 4 it? ___g_h_-_|__ 2»- 9 _colf thymus o E 4 €55- a E Z M KCI .2 8 Q 4 — I / N (I 8 3 __ u.) m O O 2 0 5 Z 2 _ 9): CL 2 8 U l *- \ block of frozen 1’. putida cells, 9510 g (wet weight), was cut into small pieces. Buffer .-\Sll (0.01 M 'l‘ris-llt'l (pll 8.0), 0.01 M .\Ig(.'l—_i, 00001 M EDTA, and 0.005 M 2-inercap- toethanol) was added (900 ml) and the mixture was stirred until a smooth cell suspension was obtained. The cell suspmision me twice passed through the pressure chamber of a .\Ianton-(iziulilt lab homogenizer (38‘) which was maintained at 7,000 psi. The process, which provided nearly complete rupture of the cells. resulted in a viscous cell extract. Pancreatic DNasc 1 (ll-5 #L’ per tnl) was added to the cell extract and the mixture was stirred for 15 min. Following centrifugation at 12,000 X g fer 30 min. the supernatant fraction was decanted and saved. The Dell“ fraction was suspended in 200 ml of Butler ASH and reccntri» fuged. The resulting supermitant fraction was combined with the supernatant fraction from the first centrifugation 01111131 extract, 2,150 ml). [fig/i. Speed Supernatant l’rttcttbrt—Jl‘lie initial extract \th centrifuged at 78,000 X g for 90 min. The clear, straw-mlnrwl supernatant fraction was collected by decantation. 'l‘ltt’ t't‘llt‘l fraction was suspemled in 200 ml of Buffer ASH and recenti'i- fused. Supernatant f1‘tt('tlt)ttS from the first and set-mid centrif- ugations were combined (high speed supernatant fraction, 1,73” ml). :ltmno-nium Sulfate (60";) Fractions—'l‘he high speed S111191113” tant fraction was diluted with buffer ASH to a protein («inventin- tion of 2.5 mg per ml. Solid ammonium sulfate (410311 “'3‘ added to the diluted high speed supernatant fraction (2500 ”ll; to give 30‘"; saturation. After stirring for 30 min, the stispett- 4 sion was centrifuged at 12,000 X g for 30 min. The supernatant . . , . ."l fraction was brought to 60f“; saturation with the addition of 4J- 9: 01 ammonium sulfate. After stirring for 30 min, insolnltlt‘ r’: .‘ ' Issue of March 10, 1971 J. C. Johnson, M. DeBacker, and J. A. Boezi 1225 Tutu: I Summary of purification The purification of RNA polymerase through the DEAR-cellu- lose fraction was conducted on material from 990 g (wet weight) of cells. After this, only one-half of the DEAE—cellulose frac- tion was processed. RNA polymerase activity was measured by the method described under “Radioactive Assay of RNA Polymerase.” gh-l DNA was used as the template. Enzyme mation l as; \ tear first; mg rmi]: unfit/mg Initialextract.........,...._....13.0 X 10‘ 99X10‘ 8 High speed supernatant fraction 6.1 X 10‘ 70 X 10‘ 11 60‘} ammonium sulfate fraction. 51 X 10‘ 270 X 10‘ 53 DEAR-cellulose fraction. . . . . , . . . 1.0 X 10‘ 330 X 10‘ 210 Phosphoccllulose Fraction I ..... 73 16 X 10‘ 2200 l’hosphocellulose Fraction II. . . . 62 2.6 X 10‘ 420 DEAEcellulose Fraction PCI. .. 30 9.6 X 10‘ 3200 DEAE-cellulose Fraction PCII . . 22 1.4 X 10‘ 640 material, which included RNA polymerase, was collected by (entrifugation. Bufier ASH (800 ml) was added and the mix- ture was stirred. The resulting solution was dialyzed for 9 hours in 12 liters of Buffer ASH (60C; ammonium sulfate fraction, 940 ml). MAE-cellulose Fraction—Acid and base~washed DEAE- cellubse suspended in Bufier ASH was poured into a column and packed under air pressure of 1 to 2 p.s.i. The packed column (14.2 X 60.0 cm) was washed with Buffer ASH until the pH of the outflow was 7.0 to 7.2. The 60‘}; ammonium sulfate frac— tion was diluted with Bufi'er ASH to a protein concentration of 8.5 mg per ml (6 liters) and applied to the column at a rate of 160 ml per min. Following application of the diluted enzyme frac- tion, the column was washed with 16 liters of Buffer ASH con- taining 0.1 M NaCl. RNA polymerase was eluted with Bufier ASH containing 0.2 M NaCl. Fractions containing RNA p0- lb'memse activity were pooled (DEAE-cellulose fraction, 5 liters). Phosphocellulose Fractions [ and [l—«Acid- and base-washed phosphocellulose was suspended in phosphate-glycerol buffer (0.02 M potassium phosphate (pH 7.5), 0.0001 M E1)TA,0.005 M 2‘mt’rcaptoethanol, and 50% glycerol (v/v)), poured into a col— umn, and packed by gravity. The packed column (5 X 40 cm) “to first washed with 750 m1 of phosphate-glycerol buffer con— mlninfi 0.5 M KCI and then with phosphateglyccrol buffer until chloride ion was no longer detected in the outflow. Th9 PH 0f the outflow was 7.5. 'The DEAE-cellulose fraction was dialyzed for 12 hours in 50 liters of a buffer containing 0.01 M Tris-HCI (pH 8.0), 00001 M EDTA, and 0.001 M 2-mercaptoethanol. Dialysis was con- tinued for 20 hours with one bufl'er change in 20 liters of phos- l’hate‘glyccrol buffer. During dialysis against phosphate- glycerol buffer, the DEAE-cellulose fraction was reduced in Volume to 1620 m1. Gli'cerol (300 ml) was added to the dialyzed DEAE—cellulose metion. The fraction was divided into two equal parts. 0116 Rm (960 ml) was stored at —20° for processing at a later date. “18 other part was applied to the phosphocellulose column at a me 013 ml per min. Following application of this enzyme fmetion, the column was washed with 4 liters of PhOSI’hi‘te' FIG. 3. Schlieren sedimentation pattern of Fractions PCI (upper) and PCII (lower). Fraction PCI at a concentration of3.4 mg per ml in a buffer containing 0.05 M Tris acetate (pH 8.0), 0.01 M magnesium acetate, 0.001 M 2-mercaptoethanol, and 0.40 M po- tassium acetate was centrifuged at 4.6" in a Kel F centerpiece in the An-l) rotor of the Spinco model E analytical ultracentrifuge. The picture was taken at 29 min after reaching a speed of 56,000 rpm. The schlicren optical system was used and the phase plate angle was 65°. Fraction PCII at a concentration of 3.3 mg per ml in a buffer containing 0.05 M Tris-HCI (pH 8.0),0.01M magnesium chloride, 0.001 M 2—mercaptoethanol, and 0.40 M potassium chlo~ ride was centrifuged at 20.1" in the Kel F centerpiece in the An-D rotor of the Spinco model E analytical ultracentrifuge. The pic- ture was taken 38 min after reaching a speed of 56,000 rpm. glycerol buffer at a rate of 5 ml per min. A linear gradient from 0.0 to 0.4 M KCI in phosphate-glycerol buffer was used to elute RNA pelymerase (Fig, 1). Two peaks of RNA polymerase activity were resolved. The first peak eluted at 0.18 M KCI and the second eluted at 0.30 M KCI. Fractions of the first peak, which had a ratio of enzyme activity of 3.0 with ghsl DNA as template to that with calf thymus DNA as template, were pooled (Fraction PCI, 480 ml). Fractions of the second peak, with an enzyme activity ratio of 0.5, were pooled (Fraction PCII, 200 ml), DEA E-rclluvlose Fractions PC] and PC] I —~DEAE-cellulose 1226 suspended in Buffer ASlI-glycm‘ol (Buffer ASH with 50‘";- glycerol (v /v)) was used to prepare two columns. The. columns, 2.5 X 19 em and 2.0 X 17 cm, were first washed with 200 ml of Buffer .—\Sll~glyccrol containing 0.5 M Na(‘l, followed by 500 ml of Buffer ASH-glycerol. In preparation for chromatogra])hy, l’hoslihocellulose Frac- tions 1 and II were ‘ach dialyzed for 10 hours in 10 liters of Buffer ASH-glycerol, and then were diluted 2—fold. l’hospho- cellulose Fraction I was applied to the larger DEAR-cellulose column and Fraction II to the smaller column. After each column was washed with a column volume of Buffcr ASH- glycerol, RNA polymerase was eluted with a linear gradient of 0.0 to 0.4 M Na(‘l. The elution profiles are presented in Fig. ‘2. For both colnn‘nis, the peak of RNA polymerase activity was eluted at 0.17 M Na(‘l. l’iak fractions from each column were pooled and dialyzed for 10 hours in ‘2 liters of a solution at 75‘} saturation with ammonium sulfate. The white flocculent pre- 1 h f l ‘7 T T «20 6‘ 'o : ENC? 2 .- e 9 E v N 8 i— 6 2 9 4- E i— to V or labeled RNA poly- merase from other sources has not been prepared. The 3 14 Specific radioactivities of the H- and C-labeled E. coli enzymes were low. Consequently, the usefulness of the preparations was limited. This study describes the . 35 Preparation and characterization of S-labeled Pseudomonas ' ' ' dio- putida RNA polymerase (aZBB'o) of high SpelelC ra activity and high specific enzymatic activity. 44 EXPERIMENTAL PROCEDURE Unless otherwise stated, the EXPERIMENTAL PRO- CEDURES used in these studies were the same as those described in the preceding chapter of the thesis. 35 Materials. S-labeled sodium sulfate with specific activity 845 mCi per mmole and Omnifluor were purchased from New England Nuclear. Triton x-lOO was from Sigma. Agarose (Bio-Gel A-l.5 m) was obtained from Bio—Rad Laboratories. Growth of Pseudomonas putida. The growth medium contained the following in grams per liter: glucose, 20; NH Cl, 2; Na HPO 6; KH PO 3; NaCl, 8; MgC12.6H20, 4 2 4’ 2 4’ 0.08; NaZSO4-10H20, 0.03; Mn(C2H302)2-4H20, 0.005; CaClzy O, 0.005; and NaZMoO4-2H20, 0.005. For 35 0.005; FeCl -6H 3 2 the production of 35S-labeled cells, 15 mCi of S-labeled sodium sulfate were added per liter of growth medium. The cells were grown at 33° on a gyrorotatory shaker in 2.8-1 Fernbach flasks containing 500 ml of growth medium. The doubling time for the culture was 100 minutes. When the cells reached the late logarithmic phase of growth, they were harvested and stored at -20°. From a three liter culture of 35S-labeled cells which had been harvested at an optical density (660 nm) of 1.3 units per ml, the Yield of cells (wet weight) was 9.7 g. 45 46 35S-labeled Proteins in polyacrylamide Assay of gels, Polyacrylamide gels were cut into 2 mm transverse fractions using a stainless steel support and cutting guide. The fractions were placed in scintillation vials. After the addition of 0.2 ml of 30% H202 to each vial, they were incubated at 65 to 70° for 9 hours or at 100 to 110° for 2 hours. Following incubation, 5 ml of a mix- ture containing 6 parts of Omnifluor solution (18.1 g of Omnifluor per gallon of toluene) and 7 parts of Triton X-100 were added to each vial (5). The vials were capped, shaken, and assayed for their 35S-content in a scintilla- tion spectrometer. RESULTS Purification of RNA Polymerase The purification of 35S-labeled RNA polymerase was performed at 0 to 40°. Initial Extract. Frozen 35S-labeled Pseudomonas putida (9.7 g) and frozen unlabeled P. putida (11.7 g) were mixed with washed glass beads (40 g) and ground in a mortar with a pestle. After cell rupture had occurred, 30 ml of buffer (10 mM Tris-HCl, pH 8.0, 10 mM MgC12, 0.1 mM EDTA, 1 mM dithiothreitol, 200 mM KCl, and 15% glycerol (v/v)) were added. The mixture was stirred until a smooth suspension was obtained. Pancreatic DNase I was added to a final concentration of 2.5 ug/ml. The mixture was stirred for 15 minutes, then centrifuged at 12,000 X g for 30 minutes. The supernatant fraction was decanted and saved. The pellet fraction was suspended in 30 ml of the above buffer and recentrifuged. The result— ing supernatant fraction was combined with the supernatant fraction from the first centrifugation. (Initial Extract, 63 ml.) High Speed Supernatant Fraction. The Initial Extract was diluted to 80 ml with the above buffer, then centrifuged at 78,000 x g for 90 minutes. The supernatant fraction was collected by decantation. (High Speed Super- natant Fraction, 64 ml.) 47 48 60% Ammonium Sulfate Fraction. Solid ammonium sulfate (23.2 g) was added to the High Speed Supernatant Fraction to give 60% of saturation. After the mixture was stirred for 15 minutes, the suspension was centrifuged at 12,000 X g for 15 minutes. The pellet fraction was dis— solved in 15 m1 of the above buffer and dialyzed against 2 liters of the buffer for 15 hours. (60% Ammonium Sulfate Fraction, 26 ml.) DEAE-Cellulose Fraction. The 60% Ammonium Sulfate Fraction was diluted 4-fold into buffer (10 mM Tris-HCl, pH 8.0, 10 mM MgCl 0.1 mM EDTA, 0.1 mM dithiothreitol, 2: and 15% glycerol (v/v)) and applied to a DEAR-cellulose column (5 by 15 cm) at a flow rate of 8 ml/min. The column was then washed with 500 ml of the above buffer containing 0.1 M NaCl. RNA polymerase was eluted with the above buffer containing 0.2 M NaCl. The fractions giving the bulk of the absorbance readings at 280 nm were pooled (230 ml). The pooled fractions were brought to 60% of saturation with solid ammonium sulfate (83.2 9). After the mixture was stirred for 15 minutes, the susPension was centrifuged at 12,000 X g for 15 minutes. The pellet fraction was dissolved in 11 m1 of phosphate buffer (20 mM potassium phosphate, pH 7.5, 1 mM dithiothreitol, 0.1 mM EDTA, and 15% glycerol (v/v)) containing 0.2 M KCl and dialyzed against 2 liters of the phosphate buffer with 0.2 M ROI for 15 hours (DEAE-cellulose Fraction, 11 m1). 49 Phosphocellulose Fraction I. The DEAF-cellulose Fraction was diluted to 31 ml with phosphate buffer and applied to a phosphocellulose column (2 by 7 cm) at a flow rate of 1 ml/min. The column was washed with 150 m1 of phosphate buffer at a flow rate of 2 ml/min. A linear gradient from 0.1 to 0.5 M KCl in phosphate buffer was used to elute RNA polymerase. Fractions (2 ml) were col- lected at a flow rate of 2 ml/min. Fractions which con- tained RNA polymerase activity that had eluted at 0.18 M KCl were pooled. The pooled fractions were dialyzed against 2 liters of 20 mM potassium phosphate, pH 7.5, 1 mM dithiothreitol, 0.1 mM EDTA, 200 mM KCl and 50% glycerol (v/v) for 5 hours and then against 2 liters of ammonium sulfate solution (75% of saturation, pH 7.5) for 12 hours. Insoluble material was collected by centrifuga- tion at 12,000 X g for 30 minutes, then dissolved in 10 mM Tris acetate, pH 8.0, 0.1 mM EDTA, 0.5 mM dithiothreitol, 500 mM KCl and 7.5% glycerol (v/v). (Phosphocellulose Fraction I, 0.83 ml.) Agarose Fraction I. Agarose beads were suspended in water, settled to remove fine material, and equili- brated in 10 mM Tris acetate, pH 8.0, 0.1 mM EDTA, 0.5 mM dithiothreitol, 500 mM KCl and 5% glycerol (v/v). A column (1.5 by 85 cm) was packed by gravity and washed with the above buffer at a flow rate of 0.2 ml/min. Phospho- cellulose Fraction I was layered on the top of the column 50 and washed through at a flow rate of 0.2 ml/min. Fractions (1.5 ml) were collected. The elution profile is presented in Figure l. Fractions 38 through 46 were pooled, dialyzed against 2 liters of 20 mM potassium phosphate, pH 7.5, 1 mM dithiothreitol, 0.1 mM EDTA, 200 mM KCl, and 50% glycerol (v/v) for 5 hours, then against 2 liters of ammo- nium sulfate solution (75% of saturation, pH 7.5) for 12 hours. Insoluble material was collected by centrifugation, dissolved in 20 mM potassium phosphate, pH 7.5, 1 mM dithiothreitol, 200 mM KCl, and 2% glycerol (v/v), and dialyzed against 200 m1 of this buffer for 12 hours. (Agarose Fraction I, 0.2 ml.) Glycerol Gradient Fraction I. Agarose Fraction I was layered on a 10 to 30% linear glycerol gradient (4.8 ml) prepared in 50 mM potassium phosphate, pH 7.5, 1 mM dithiothreitol and 200 mM KCl and centrifuged in the SW 39 rotor of the Spinco model L-2 centrifuge at 35,000 rpm for 19.1 hours at 4°. After centrifugation, a hole was punched in the bottom of the centrifuge tube and twenty 35S-content of each fraction fractions were collected. The was measured (Figure 2). Fractions 5 through 9 were pooled and dialyzed against 500 ml of 50 mM Tris acetate, pH 8.0, 10 mM magnesium acetate, 1 mM dithiothreitol, 0.1 mM EDTA, 200 mM KCl, and 50% glycerol (v/v) for 8 hours. (Glycerol Gradient Fraction I, 0.58 ml.) Glycerol Gradient Fraction I was stored at -20° at a protein concentration of 1 mg/ml. 51 .cwaoom mHm3 we cmsounu mm mCOfiuomum .H mHoHpH< mo =Ammmumewaom 42m mo wmmmm m>HuomoHUmmv mhspmooum Hmucmfi Iflummxmz ca pmbflnowmp posses one ou mcflpsooom mmHsuxHE coeuommu a: mma :H mmHQEMm Halm co pmcwfiumump mm3 A4 4V >9H>fluom wmmumE»Hom mp mmz CEDHOU was .Houmowam wm paw .Hox 2E oom .Houamunuoaspas :5 m.o .«eom 2s H.o .o.m mm .wumumom mane 2s as ea emumunaeesam ammn can guess season mmoumod EU mm an m.H 6 Op GHE\HE ~.o mo mums 30am 0 pm pmflammm mm3 AHE mm.ov H cofluomum mmoHsHHmoonmmocm H coeuomsm mmoHsaamoocmmocm mo coaumuuaflm How mmoumm3 pmumoflpcw munmflm3 Hmasowaoe mDOHHm> may mo mcflmco mpwummmhaom may mo Goes lemon one .5: own an Umccmom mmz How may .mcwcflmummp mcfl3oaaom .msan mammmfioou cufls cwcflmum mm3 cflmuoum was .mom wH.o can .H.h mm .mumzmmocm Eswpom z H.o mcwcflmucoo Hmmmsn m as Hmm\mE m um meson m.~ How omm um meuom Inmm mm3 mammuozmosuomam .Houmomam wm.ma paw mpHEm Iamuom wmh.m mcHsHmucoo musuxwfi momlmcwfimawuom cm Eoum pwummmnm Hmm mcwfimamhomwaomnmam So HH 0 :0 command mm3 Acflmuoum m: oav musyxfle mnu mo mamfimm alum 4 .Houmowam wm can .Hocmcumoummoumfium wo.a .mom mo.H .H.> mm .mumnmmonm Esapom Z H.o mcwcflmucoo cowusaom 0 no a: om CH mmuscwE OH How oooa um pmumnsocfl mm3 pomuuxm HmfiuflcH mo samuoum m: ooa mcwcwmucou wnsuxflfi 4 uomnuxm HMfluHcH mo How mpflfimamuommaomlmam am no masoche Ufluumfifimcmolu.v mmeHm 60 OOO'OI _) OOO‘BI —) OOO'OG —_) E OOO'OOI ———) OOO'OGZ ——’ ugbuo —-> um 099 lv 30stsossv DISTANCE FROM ORIGIN 61 358 analysis of sections of this gel (Figure 5) also led to the conclusion that 8' plus B amounted to 1.2% of the total protein of the Initial Extract. Since 8' plus B are 63% (by weight) of the holoenzyme (0288'0), the holoenzyme could amount to 2% of the total protein of the Initial Extract. Accordingly, the yield of RNA polymerase in the Glycerol Gradient Fraction I was 2.5% of the estimated amount present in the Initial Extract. An estimation of the percent by weight in the Initial Extract of polypeptide chains of various molecular weights can be made from Figures 3 and 4. The per cent of polypeptide chains that have molecular weights greater than 25,000, 50,000, and 100,000 was 75, 31, and 9% respectively. One-half of the polypeptide chains have molecular weights greater than 36,000. Characterization of 35S-labeled RNA Polymerase Specific enzymatic activity and specific radio- activity of 35S-labeled RNA polymerase. The specific enzymatic activity of 35S-labeled RNA polymerase (Glycerol Gradient Fraction I) was 7,800 mnoles of CMP incorporated per hour per mg of protein at 30° using gh-l DNA as the template. With calf thymus DNA as the template, the The specific radio- 3 x 107 cpm Specific enzymatic activity was 3,300. activity of 35s—labeled RNA polymerase was 2. per mg of protein. -—- ——-—-——-—- ——-—- —::uL—.m 62 12% opHanxnoomHom cw mcflououm poaonmalmmm mo mommfiv onsoooonm HoucoEHuomxme CH ponfluomoo oonuoE onu ou mchHooom commando moz coauomnw nomo wo uconcoo mmm one .Anooo 88 my oceauoosw mm owns #50 mo3 v onsmflm ca pounomosm mnfloonu UHHpoEHmnop onu mn commaoco moz nOHnS poouuxm HMflanH mo Hom opflanwuoowaomlmom pocflmum osan owmmofioou one vooupxm HofluwnH mo How o©Hanmsoomaomlmom no mo mwmwamnm mmMIu.m mmame 63 OOO‘OI OOO'QI 000'? Z OOO'OG OOO'OOI OOO‘OQI OOO'OOZ OOO'OGZ ugbuo 20 I K) I 2 ID (”pl x mm) 592 50 4O 3O 20 I0 FRACTION NUMBER 64 Stability of 35S-labeled RNA polymerase. Another preparation of 35S-labeled RNA polymerase which had been purified through the Agarose gel filtration step was used in the study of the stability of 35S-1abeled enzyme. This preparation of enzyme had a specific enzymatic activity of 8,700 nmoles of CMP incorporated per hour per mg of protein using gh-l DNA as the template. The specific radioactivity was 7 x 106 cpm per mg of protein. The preparation of enzyme was stored at a protein concentra- tion of 6 mg/ml at -20° in 50 mM Tris acetate, pH 8.0, 10 mM magnesium acetate, 0.1 mM EDTA, 1 mM dithiothreitol, 200 mM KCl, and 50% glycerol (v/v). After 90 days which is slightly more than the 87.9 day half-life of 355, 80 to 90% of the enzymatic activity was retained. . 35 SDS-polyacrylamide gel electrophoresis of S- labeled RNA polymerase. The B', B, o and 0 subunits of the 35S-labeled enzyme were resolved by SDS-polyacrylamide gel electrophoresis (Figure 6). A densimetric tracing of a Coomassie blue stained SDS-polyacrylamide gel is pre- sented in Figure 7. As determined from measurements of the area under each subunit peak, the amount of 8' plus B and of a relative to a was 3.7 to 1.1 to 1.0, respectively. The amount of 8' was equal to the amount of 8 (Figure 8). As calculated from the relative amounts of the subunits and their relative molecular weights, the subunit struc— tural formula for the 35S-labeled enzyme was 0288'0. 65 FIGURE 6.--SDS-polyacrylamide Gel Electrophoresis of Glycerol Gradient Fraction I A mixture containing 30 09 protein of Glycerol Gradient Fraction I was incubated at 100° for 10 minutes in 60 ul of a solution containing 0.1 M sodium phosphate, pH 7.1, 1.0% SDS, 1.0% 2- mercaptoethanol, and 5% glycerol. A 4-ul sample of the mixture (2 pg protein) was layered on an 11 cm SDS-polyacrylamide gel prepared from an acrylamide-SDS mixture containing 3.75% acrylamide. Electrophoresis was performed at 25° for 4.75 hours at 8 ma/gel in a buffer (0.1 M sodium phos- phate, pH 7.1, and 0.1% SDS). The protein was stained with Coomassie blue. H, ,. -‘o..~w 67 .uuommcmuu Hooded puowaflw o mcwms Ed omm um oboe mos mcfloonu oeuuoefimcop one .oan owmmmEoou nuflz confloum wok neonosm one .0 ossmflm on pcomoa on» Ce confluomon mm memoHonQouuooHo Hom oUHanwuoomaomlQO en pouhaono mo3 H coeuooum unofipmnw Honoohaw mo onEmm mnlm a H noflnoouh ucowpouw Houoohao mo How opHE IoH>HomwaomlQO no mo mneoone oeunofiflmcoall.h mmDUHm 68 I11“ 099 1V EONVBEIOSBV DI STANCE FROM ORIGIN 69 FIGURE 8.--Densimetric Tracing of the B' and 8 Region of an SDS-polyacrylamide Gel of Glycerol Gradient Fraction I A 2-ug sample of Glycerol Gradient Fraction I was analyzed by SDS-polyacrylamide gel electro- phoresis according to the legend to Figure 6 except that electrophoresis was for 6 hours. The gel was stained with Coomassie blue and scanned using a Joyce-Loebel Microdensitometer. 70 Ecomm ._.< mozHooeHom CH mceoeoem poHoannmmm Ho hmmmflv ouspoooum HoecoEHHomxm= :H poneuomop poneoE one oe manHoooo UonHoco mm3 coHeomHH nooo Ho ecoecoo mmm one .Anomo as my mcoHeooHe om oenH e50 wm3 m ousmem CH poecomoem mneooue UHHeoEHmnop one an ponHoco moz noenB H noeeooum.enoepouo HouoohHw Ho Hom ooHEMHmuoomHomlmom pocemem oan onmmEoou one H coHeoon ecoepouw HouooeHw Ho How owesmHmsommHOQImom cm mo memmHmss mmm:u.m mmooem 73 mmmZDZ 20:04.1“. 1 00 (t-Ol x de) 392 74 TABLE 2.——3SS Content of 8' Relative to B Experiment 355 in B' 358 in B 358 Content of 8' (cpm) (cpm) Relative to B 1 800 790 1.01 2 1490 1380 V 1.08 3 1510 1650 0.92 75 o.H o.H m.o m.o a o.H o.H m.o m.o a w.v o.m N.~ H.H o N.e o.m m.m m.H m m.e o.m m.m m.H .m ceonu opeemom meHGDQSm useom pecansm no a ooo.ee muecsnsm mueasnsm mom ecoecou Mom ecoecou Ho ecoecou Ho eanoz an eecsndm Mmm o>HemHom mmm o>HeMHom mmm o>HeMHom enDOEd o>HeMHom opeemommHom e 0e o>eeMHom o pnm .m ..m e0 enoecoo m ||.m mqmne mm DISCUSSION 35S-labeled Pseudomonas putida RNA polymerase (0288'0) was purified from labeled cells grown on minimal growth medium containing 35S-labeled Sulfate. The speci- fic radioactivity of the pure enzyme was 2.3 X 107 cpm per mg protein. As a result of this high specific radioacti- vity, the radioactive assay used for protein quantitation was sensitive to 0.01 pg protein. As calculated from the 35 known specific radioactivity of the S-labeled sulfate used in the growth medium, one sulfur atom in approxi- mately 20,000 was radioactive. If each RNA polymerase molecule contains 400 sulfur atoms, one enzyme molecule in every 50 contains a 358 atom. The amount of 8' plus B in the Initial Extract was 1.2% by weight as determined by SDS-polyacrylamide gel electrophoresis. From the percent by weight of 0288'0 in the Initial Extract, the molecular weight of 0288'0 (5.06 105 daltons), and assuming that the Coomassie blue stain reacts with the polypeptides of the Initial Extract equi- valently it was calculated that each bacterial cell con- tains approximately 5,000 molecules of aZBB'G. This preparation of 35S-labeled RNA polymerase is being used in the study of the release of the a subunit 76 77 from the holoenzyme (0288'0) during the RNA synthetic process (7 and unpublished results). The results of this study have shown that c is released following the binding of the holoenzyme to poly(A), poly(U), or to native P. putida DNA. The a subunit is not released following the binding of the holoenzyme to poly[d(A-T)], native gh-l DNA; denatured gh-l or denatured P. putida DNA. Following the initiation of RNA synthesis on native gh-l DNA as the template, 0 is released from the enzyme. This result provides the first direct experimental evidence for the in zit£g_release of O as described in the sigma cycle proposed by Travers and Burgess (8). REFERENCES Lowry, O. H., Rosenbrough, N. J., Farr, A. L., and Randall, R. J., J. Biol. Chem., 193, 265 (1951). Goff, C. G., and Weber, K., Cold Spring Harbor Sym- posia on Quantitative Biology, 35, Cold Spring Harbor Laboratory, New York, 1970, p. 101. Ihler, G. M., Biochim. Biophys. Acta, 213, 523 (1970). Stevens, A., Biochem. Biophys. Res. Comm., 41, 367 (1970). Tishler, P. V., and Epstein, C. J., Anal. Biochem., 22, 89 (1968). Bray, G. A., Anal. Biochem., l, 279 (1960). Gerard, G. F., Johnson, J. C., and Boezi, J. A., Fed. Proceedings, (1971) in press. Travers, A. A., and Burgess, R. R., Nature, 2 2, 537 (1969). 78 ‘IIIIIIIIIII IIIIIIIIIIIIIIIIIIIIIIIIII 3 2 7 2 2 6 o 3 O 3 9 2 4| Ii