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Abstract
The single-stranded DNA-binding protein (SSB) of Escherichia coli is involved in all aspects of DNA metabolism: replication, repair, and recombination. In solution, the protein exists as a homotetramer of 18,843-kilodalton subunits. As it binds tightly and cooperatively to single-stranded DNA, it has become a prototypic model protein for studying protein-nucleic acid interactions. The sequences of the gene and protein are known, and the functional domains of subunit interaction, DNA binding, and protein-protein interactions have been probed by structure-function analyses of various mutations. The ssb gene has three promoters, one of which is inducible because it lies only two nucleotides from the LexA-binding site of the adjacent uvrA gene. Induction of the SOS response, however, does not lead to significant increases in SSB levels. The binding protein has several functions in DNA replication, including enhancement of helix destabilization by DNA helicases, prevention of reannealing of the single strands and protection from nuclease digestion, organization and stabilization of replication origins, primosome assembly, priming specificity, enhancement of replication fidelity, enhancement of polymerase processivity, and promotion of polymerase binding to the template. E. coli SSB is required for methyl-directed mismatch repair, induction of the SOS response, and recombinational repair. During recombination, SSB interacts with the RecBCD enzyme to find Chi sites, promotes binding of RecA protein, and promotes strand uptake.
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Affiliation(s)
- R R Meyer
- Department of Biological Sciences, University of Cincinnati, Ohio 45221
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2
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Shwartz H, Livneh Z. Dynamics of termination during in vitro replication of ultraviolet-irradiated DNA with DNA polymerase III holoenzyme of Escherichia coli. J Biol Chem 1987. [DOI: 10.1016/s0021-9258(18)60992-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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3
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Livneh Z. Replication of UV-irradiated single-stranded DNA by DNA polymerase III holoenzyme of Escherichia coli: evidence for bypass of pyrimidine photodimers. Proc Natl Acad Sci U S A 1986; 83:4599-603. [PMID: 2941756 PMCID: PMC323788 DOI: 10.1073/pnas.83.13.4599] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Replication of UV-irradiated circular single-stranded phage M13 DNA by Escherichia coli RNA polymerase (EC 2.7.7.6) and DNA polymerase III holoenzyme (EC 2.7.7.7) in the presence of single-stranded DNA binding protein yielded full-length as well as partially replicated products. A similar result was obtained with phage G4 DNA primed with E. coli DNA primase, and phage phi X174 DNA primed with a synthetic oligonucleotide. The fraction of full-length DNA was several orders of magnitude higher than predicted if pyrimidine photodimers were to constitute absolute blocks to DNA replication. Recent models have suggested that pyrimidine photodimers are absolute blocks to DNA replication and that SOS-induced proteins are required to allow their bypass. Our results demonstrate that, under in vitro replication conditions, E. coli DNA polymerase III holoenzyme can insert nucleotides opposite pyrimidine dimers to a significant extent, even in the absence of SOS-induced proteins.
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Mechanism of replication of ultraviolet-irradiated single-stranded DNA by DNA polymerase III holoenzyme of Escherichia coli. Implications for SOS mutagenesis. J Biol Chem 1986. [DOI: 10.1016/s0021-9258(18)67689-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Nesvera J, Hochmannová J. DNA-protein interactions during replication of genetic elements of bacteria. Folia Microbiol (Praha) 1985; 30:154-76. [PMID: 2581876 DOI: 10.1007/bf02922209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Specific interactions of DNA with proteins are required for both the replication of deoxyribonucleic acid proper and its regulation. Genetic elements of bacteria, their extrachromosomal elements in particular, represent a suitable model system for studies of these processes at the molecular level. In addition to replication enzymes (DNA polymerases), a series of other protein factors (e.g. topoisomerases, DNA unwinding enzymes, and DNA binding proteins) are involved in the replication of the chromosomal, phage and plasmid DNA. Specific interactions of proteins with DNA are particularly important in the regulation of initiation of DNA synthesis. Association of DNAs with the cell membrane also plays an important role in their replication in bacteria.
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6
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Matson SW, Richardson CC. Nucleotide-dependent binding of the gene 4 protein of bacteriophage T7 to single-stranded DNA. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)89551-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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7
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Meyer RR, Brown CL, Rein DC. A new DNA-dependent ATPase from Escherichia coli. Purification and characterization of ATPase IV. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)42961-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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8
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Marians KJ. Enzymology of DNA in replication in prokaryotes. CRC CRITICAL REVIEWS IN BIOCHEMISTRY 1984; 17:153-215. [PMID: 6097404 DOI: 10.3109/10409238409113604] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
This review stresses recent developments in the in vitro study of DNA replication in prokaryotes. New insights into the enzymological mechanisms of initiation and elongation of leading and lagging strand DNA synthesis in ongoing studies are emphasized. Data from newly developed systems, such as those replicating oriC containing DNA or which are dependent on the lambda, O, and P proteins, are presented and the information compared to existing mechanisms. Evidence bearing on the coupling of DNA synthesis on both parental strands through protein-protein interactions and on the turnover of the elongation systems are analyzed. The structure of replication origins, and how their tertiary structure affects recognition and interaction with the various replication proteins is discussed.
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Ogawa T, Arai K, Okazaki T. Site selection and structure of DNA-linked RNA primers synthesized by the primosome in phage phi X174 DNA replication in vitro. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44124-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Hübscher U. DNA polymerases in prokaryotes and eukaryotes: mode of action and biological implications. EXPERIENTIA 1983; 39:1-25. [PMID: 6297955 DOI: 10.1007/bf01960616] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Wolfson R, Eisenberg S. Escherichia coli host factor required specifically for the phi X174 stage III reaction: in vitro identification and partial purification. Proc Natl Acad Sci U S A 1982; 79:5768-72. [PMID: 6225114 PMCID: PMC346991 DOI: 10.1073/pnas.79.19.5768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A cell-free extract prepared from phi X174-infected Escherichia coli cells sustained in vitro synthesis of viral DNA (stage III reaction) when supplemented with fraction II from uninfected cells. The reaction was dependent upon deoxyribonucleoside triphosphate, ATP, added phi X174 replicative form I DNA template, and the fraction II from uninfected cells. This reaction differed from the stage II reaction (semiconservative replication of duplex replicative form DNA) by the production of stable viral protein-DNA complexes sensitive to anti-phi X174 antiserum. Three types of protein-DNA complexes were identified, 50S, 92S, and a 114S complex that cobanded in CsCl and cosedimented in neutral sucrose gradients with a phi X174 phage marker. The sensitivity of these complexes to anti-phi X174 antiserum and Staphylococcus aureus provided a relatively rapid biochemical assay for direct measurement of the amount of DNA synthesized by the stage III reaction. With this assay, an E. coli factor (SIII) required specifically for the synthesis of viral protein-DNA complexes was identified and purified 200-fold from uninfected E. coli cells. The partially purified SIII factor was required for the synthesis of DNA and viral protein-DNA complexes in the phi X174-infected cell extracts and could not be replaced by rep protein, single-strand binding protein, or DNA polymerase III holoenzyme.
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Thomas DC, Meyer RR. Deoxyribonucleic acid dependent adenosinetriphosphatases from the Novikoff hepatoma. Characterization of a homogeneous adenosinetriphosphatase that stimulates DNA polymerase beta. Biochemistry 1982; 21:5060-8. [PMID: 6128027 DOI: 10.1021/bi00263a033] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Five chromatographically distinct DNA-dependent ATPase activities have been identified in high salt-detergent extracts of the Novikoff hepatoma. One of these, ATPase III, has been purified to apparent homogeneity as judged by polyacrylamide gel electrophoresis and has a specific activity of 12 mumol of ATP hydrolyzed min-1 (mg of protein)-1. The enzyme, a dimer of Mr 65000 subunits, has a sedimentation coefficient of 7.0 S in both high salt and low salt, a Stokes radius of 43 A, and a frictional coefficient of 1.31. In the presence of Mg2+ ion and a polynucleotide effector, the enzyme catalyzes hydrolysis of ATP or dATP to a diphosphate with a Km of 206 microM and 110 microM, respectively, for the two substrates. Although single-stranded effectors are preferred, the enzyme has significant activity with double-stranded effectors. The Km for effector is 0.4 microM (nucleotide). The analogues adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), dideoxyadenosine triphosphate (ddATP), and adenosine 5'-(alpha, beta-methylenetriphosphate) (alpha, beta-Me-ATP) are competitive inhibitors of the enzyme while adenosine tetraphosphate (ATP-P), 8-bromoadenosine 5'-triphosphate (8-Br-ATP), 5'-adenylyl imidodiphosphate (AMP-PNP), and adenosine 5'-(beta, gamma-methylenetriphosphate) (beta, gamma-Me-ATP) do not inhibit. The enzyme is insensitive to nalidixic acid, novobiocin, and berenil but is sensitive to N-ethylmaleimide. ATPase III is capable of stimulating DNA polymerase beta on duplex DNA, but this effect is abolished in the presence of ATP gamma S. Polymerase stimulation is further enhanced in the presence of a single-stranded DNA-binding protein. These data suggest that ATPase III may play a role in DNA repair.
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Protein n, a primosomal DNA replication protein of Escherichia coli. Purification and characterization. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(20)65130-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Kaguni JM, Kornberg A. The rho subunit of RNA polymerase holoenzyme confers specificity in priming M13 viral DNA replication. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)83796-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Kuwabara N, Uchida H. Functional cooperation of the dnaE and dnaN gene products in Escherichia coli. Proc Natl Acad Sci U S A 1981; 78:5764-7. [PMID: 6458043 PMCID: PMC348855 DOI: 10.1073/pnas.78.9.5764] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A system was designed to isolate second-site intergenic suppressors of a thermosensitive mutation of the dnaE gene of Escherichia coli. The dnaE gene codes for the alpha subunit of DNA polymerase III [McHenry, C. S. & Crow, W. (1979) J. Biol. Chem. 254, 1748-1753]. One such suppressor, named sueA77, was finely mapped and found to be located at 82 min on the E. coli chromosome, between dnaA and recF, and within the dnaN gene [Sakakibara, Y. & Mizukami, T. (1980) Mol. Gen. Genet. 178, 541-553]. The dnaN gene codes for the beta subunit of DNA polymerase III holoenzyme [Burgers, P. M. J., Kornberg, A. & Sakakibara, Y. (1981) Proc. Natl. Acad. Sci. USA 78, 5391-5395]. The sueA77 mutation was trans-dominant over its wild-type allele, and it suppressed different thermosensitive mutations of dnaE with different maximal permissive temperature. These properties were interpreted as providing genetic evidence for interaction of the dnaE and dnaN gene products in E. coli.
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Taketo A. Effect of the dnaN mutation on the growth of small DNA phages. MOLECULAR & GENERAL GENETICS : MGG 1981; 183:130-3. [PMID: 6460152 DOI: 10.1007/bf00270150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effect of the dnaN mutation on the growth of single-stranded DNA phages was studied by burst experiments. In HC138 dnaN cells exposed to 42.5 degrees C at 5 min before infection, growth of spherical (microvirid or isometric) phages such as alpha 3, phi Kh-1 and phi X174 was partially reduced at the nonpermissive temperature. When infection was performed at 30 min after temperature shift-up, viral replication was completely inhibited at 42.5 degrees C in the dnaN strain but not in a dna+ revertant. At 41 degrees C, multiplication of filamentous (inovirid) phages M13 and fd was restricted specifically in HC138 F+ dnaN bacteria. When dnaN cells lysogenic for lambda i21 were grown at 42.5 degrees C for 60 min and then shifted down to 33 degrees C, a burst of lambda i21 occurred with concomitant cellular lysis, manifesting induction of the prophage development.
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Badaracco G, Ginelli E, Sacchi N, Sora S, Plevani P. DNA synthesis catalyzed in vitro by yeast extracts. EUROPEAN JOURNAL OF BIOCHEMISTRY 1981; 118:247-54. [PMID: 6169527 DOI: 10.1111/j.1432-1033.1981.tb06393.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A procedure to prepare crude extracts from single colonies of Saccharomyces cerevisiae is described. Partially purified extracts catalyzed DNA synthesis directed by single-stranded fd DNA. Maximum activity requires the presence of ribonucleoside triphosphates although extensive DNA synthesis is observed in the presence of only deoxynucleoside triphosphates. Alkaline sucrose gradient analysis demonstrated that initiation of new DNA chains occurs in vitro and the DNA products synthesized are heterogeneous in size, Isopycnic analysis of the products of ribonucleotide-initiated fd DNA replication showed covalent linkage between the initiator RNA and the newly synthesized DNA. The fd-replicating capacity of extracts prepared from cell-division-cycle mutants, defective in events controlling DNA initiation of elongation, showed an increased thermosensitivity in the DNA replication reaction in vitro.
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Arai K, Kornberg A. Mechanism of dnaB protein action. IV. General priming of DNA replication by dnaB protein and primase compared with RNA polymerase. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69397-x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Arai K, Yasuda S, Kornberg A. Mechanism of dnaB protein action. I. Crystallization and properties of dnaB protein, an essential replication protein in Escherichia coli. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69394-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Arai K, Low RL, Kornberg A. Movement and site selection for priming by the primosome in phage phi X174 DNA replication. Proc Natl Acad Sci U S A 1981; 78:707-11. [PMID: 6262762 PMCID: PMC319871 DOI: 10.1073/pnas.78.2.707] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The Escherichia coli priming system used for initiation of DNA chains on phage phi X174 single-stranded DNA is a multiprotein unit called the primosome [Arai, K. & Kornberg. A. (1981) Proc. Natl. Acad. Sci. USA 78, 69-73]. Assembled with participation of seven prepriming proteins and primase at a unique place on the phi X174 DNA template, the primosome is bound tightly to the DNA, yet moves rapidly and unidirectionally opposite to primer and DNA chain synthesis. Contributions of protein n' and dnaB protein, two components of the primosome, to movement and site selection for priming are considered in this report. Figuratively, the primosome can be likened to a locomotive that depends on protein n' as its engine and dnaB protein as the engineer. Protein n', a DNA-dependent ATPase (dATPase) appears to use the energy of hydrolysis of the nucleoside triphosphate for processive translocation of the primosome. dnaB protein, A DNA-dependent ribonucleosidetriphosphatase, depends on allosteric effects of a nucleoside triphosphate to induce changes in the structure of the single-stranded DNA at preferred sequences that enable primase to synthesize a short primer for initiation of DNA synthesis (unpublished data). These primosome properties have important implications for the progress of the replication fork of the E. coli chromosome.
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Keller SJ, Ho C. Chloroplast DNA Replication in Chlamydomonas reinhardtii. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/s0074-7696(08)62322-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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Hübscher U, Kornberg A. The dnaZ protein, the gamma subunit of DNA polymerase III holoenzyme of Escherichia coli. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70189-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Mosbaugh D, Meyer R. Interaction of mammalian deoxyribonuclease V, a double strand 3' to 5' and 5' to 3' exonuclease, with deoxyribonucleic acid polymerase-beta from the Novikoff hepatoma. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70455-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Nomura N, Ray DS. Expression of a DNA strand initiation sequence of ColE1 plasmid in a single-stranded DNA phage. Proc Natl Acad Sci U S A 1980; 77:6566-70. [PMID: 7005899 PMCID: PMC350326 DOI: 10.1073/pnas.77.11.6566] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
In order to investigate initiation of H-strand (lagging strand) replication of the plasmid ColE1, the origin region fragment (Hae II-E) of ColE1 was inserted into the intergenic region of filamentous DNA phage M13 and cloned. A site capable of promoting DNA strand initiation on a single-stranded DNA template has been detected on the L-strand (leading strand) of the cloned fragment. The site, named rri-1 rifampicin-resistant initiation), directs conversion of chimeric phage single-stranded DNA to parental replicative form in the presence of rifampicin, which blocks the function of the complementary strand origin of M13. The function of rri-1 is dependent on both the dnaG and dnaB gene products. It is postulated that rri-1 might be an initiation site for synthesis of the lagging DNA strand during unidirectional replication of ColE1 DNA.
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Hübscher U, Lutz H, Kornberg A. Novel histone H2A-like protein of escherichia coli. Proc Natl Acad Sci U S A 1980; 77:5097-101. [PMID: 7001471 PMCID: PMC350003 DOI: 10.1073/pnas.77.9.5097] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
A histone-like protein (H) from Escherichia coli has been purified to more than 98% homogeneity by using its capacity to inhibit DNA functions. H protein behaves as a dimer of 28,000-dalton subunits. The histone H2A-like properties of H protein are: (i) binding to DNA at a stoichiometry of 1 H protein dimer per 75 bases; (ii) abundance of about 30,000 molecules per cell, sufficient to bind about 20% of the chromosome; (iii) limiting digestion of double-stranded DNA by micrococcal nuclease; (iv) reannealing of complementary single-stranded DNA; (v) amino acid composition resembling that of eukaryotic histone H2A; (vi) neutralization of H protein by antibody specific for H2A; (vii) heat stability; and (viii) acid solubility. The capacity of H protein to bind DNA prevents its template or substrate functions n several reactions in vitro: DNA synthesis by several polymerases; transcription by RNA polymerase; DNA topoisomerase activity; and DNA-dependent ATP hydrolysis by rep protein, dnaB protein, or protein n'. Together with other histone-like proteins of E. coli, H protein may organize the E. coli chromosome into nucleosomes, such as in eukaryotic chromatin.
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Arai K, Arai N, Shlomai J, Kornberg A. Replication of duplex DNA of phage phi X174 reconstituted with purified enzymes. Proc Natl Acad Sci U S A 1980; 77:3322-6. [PMID: 6447874 PMCID: PMC349607 DOI: 10.1073/pnas.77.6.3322] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Replication of the covalently closed duplex replicative form (RF) of phage phi X174 DNA has been achieved by coupling two known enzyme systems: (i) synthesis of viral strand circles (SS) from RF, and (ii) conversion of SS to nearly complete RF (RF II). In this coupled system, activated RF (gene A . RF II complex) was a more efficient template and generated as many as 10 RF II molecules per RF input, at a rate commensurate with SS synthesis. The 11 proteins required for the two component systems were all needed in the coupled RF duplication system; no new factors were required. Single-stranded DNA binding protein was needed for RF duplication at only 4% the level needed in its stoichiometric participation in SS synthesis. In addition to RF II, more complex replicative forms appeared late in the reaction, and their possible origin is discussed.
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Shlomai J, Kornberg A. An Escherichia coli replication protein that recognizes a unique sequence within a hairpin region in phi X174 DNA. Proc Natl Acad Sci U S A 1980; 77:799-803. [PMID: 6444725 PMCID: PMC348368 DOI: 10.1073/pnas.77.2.799] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Protein n', a prepriming DNA replication enzyme of Escherichia coli, is a phi X174 DNA-dependent ATPase. Restriction of phi X174 DNA have led to the identification of a 55-nucleotide fragment that carries the protein n' recognition sequence. Molecular hybridization and sequence analysis have located this sequence within the untranslated region between genes F and G, a map location analogous to that of the unique complementary strand origin of phage G4 DNA. Within the 55-nucleotide fragment is a sequence of 44 nucleotides that forms a stable hairpin structure. This duplex may be the signal for protein n' to initiate the prepriming events that led to the start of phi X174 complementary DNA strand replication.
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