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Rechkunova NI, Lavrik OI. Photoreactive DNA as a Tool to Study Replication Protein A Functioning in DNA Replication and Repair. Photochem Photobiol 2020; 96:440-449. [PMID: 32017119 DOI: 10.1111/php.13222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 12/08/2019] [Indexed: 11/30/2022]
Abstract
Replication protein A (RPA), eukaryotic single-stranded DNA-binding protein, is a key player in multiple processes of DNA metabolism including DNA replication, recombination and DNA repair. Human RPA composed of subunits of 70-, 32- and 14-kDa binds ssDNA with high affinity and interacts specifically with multiple proteins. The RPA heterotrimer binds ssDNA in several modes, with occlusion lengths of 8-10, 13-22 and 30 nucleotides corresponding to global, transitional and elongated conformations of protein. Varying the structure of photoreactive DNA, the intermediates of different stages of DNA replication or DNA repair were designed and applied to identify positioning of the RPA subunits on the specific DNA structures. Using this approach, RPA interactions with various types of DNA structures attributed to replication and DNA repair intermediates were examined. This review is dedicated to blessed memory of Prof. Alain Favre who contributed to the development of photoreactive nucleotide derivatives and their application for the study of protein-nucleic acids interactions.
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Affiliation(s)
- Nadejda I Rechkunova
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, Russia.,Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
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Krasikova YS, Rechkunova NI, Lavrik OI. Replication protein A as a major eukaryotic single-stranded DNA-binding protein and its role in DNA repair. Mol Biol 2016. [DOI: 10.1134/s0026893316030080] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Pestryakov PE, Lavrik OI. Mechanisms of single-stranded DNA-binding protein functioning in cellular DNA metabolism. BIOCHEMISTRY (MOSCOW) 2009; 73:1388-404. [PMID: 19216707 DOI: 10.1134/s0006297908130026] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review deals with analysis of mechanisms involved in coordination of DNA replication and repair by SSB proteins; characteristics of eukaryotic, prokaryotic, and archaeal SSB proteins are considered, which made it possible to distinguish general mechanisms specific for functioning of proteins from organisms of different life domains. Mechanisms of SSB protein interactions with DNA during metabolism of the latter are studied; structural organization of the SSB protein complexes with DNA, as well as structural and functional peculiarities of different SSB proteins are analyzed.
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Affiliation(s)
- P E Pestryakov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
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Dickson AM, Krasikova Y, Pestryakov P, Lavrik O, Wold MS. Essential functions of the 32 kDa subunit of yeast replication protein A. Nucleic Acids Res 2009; 37:2313-26. [PMID: 19244309 PMCID: PMC2673435 DOI: 10.1093/nar/gkp090] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Replication protein A (RPA) is a heterotrimeric (70, 32 and 14 kDa subunits), single-stranded DNA-binding protein required for cellular DNA metabolism. All subunits of RPA are essential for life, but the specific functions of the 32 and 14 kDa subunits remains unknown. The 32 kDa subunit (RPA2) has multiple domains, but only the central DNA-binding domain (called DBD D) is essential for life in Saccharomyces cerevisiae. To define the essential function(s) of RPA2 in S. cerevisiae, a series of site-directed mutant forms of DBD D were generated. These mutant constructs were then characterized in vitro and in vivo. The mutations had minimal effects on the overall structure and activity of the RPA complex. However, several mutants were shown to disrupt crosslinking of RPA2 to DNA and to dramatically lower the DNA-binding affinity of a RPA2-containing subcomplex. When introduced into S. cerevisiae, all DBD D mutants were viable and supported normal growth rates and DNA replication. These findings indicate that RPA2–DNA interactions are not essential for viability and growth in S. cerevisiae. We conclude that DNA-binding activity of RPA2 is dispensable in yeast and that the essential function of DBD D is intra- and/or inter-protein interactions.
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Affiliation(s)
- Anne M Dickson
- Department of Biochemistry, University of Iowa College of Medicine, Iowa City, IA 52242-2600, USA
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Petruseva IO, Tikhanovich IS, Chelobanov BP, Lavrik OI. RPA repair recognition of DNA containing pyrimidines bearing bulky adducts. J Mol Recognit 2008; 21:154-62. [PMID: 18438969 DOI: 10.1002/jmr.877] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Recognition of new DNA nucleotide excision repair (NER) substrate analogs, 48-mer ddsDNA (damaged double-stranded DNA), by human replication protein A (hRPA) has been analyzed using fluorescence spectroscopy and photoaffinity modification. The aim of the present work was to find quantitative characteristics of RPA-ddsDNA interaction and RPA subunits role in this process. The designed DNA structures bear bulky substituted pyrimidine nitrogen bases at the inner positions of duplex forming DNA chains. The photoreactive 4-azido-2,5-difluoro-3- pyridin-6-yl (FAP) and fluorescent antracenyl, pyrenyl (Antr, Pyr) groups were introduced via different linker fragments into exo-4N of deoxycytidine or 5C of deoxyuridine. J-dU-containing DNA was used as a photoactive model of undamaged DNA strands. The reporter group was a fluorescein residue, introduced into the 5'-phosphate end of one duplex-forming DNA strand. RPA-dsDNA association constants and the molar RPA/dsDNA ratio have been calculated based on fluorescence anisotropy measurements under conditions of a 1:1 RPA/dsDNA molar ratio in complexes. The evident preference for RPA binding to ddsDNA over undamaged dsDNA distinctly depends on the adduct type and varies in the following way: undamaged dsDNA < Antr-dC-ddsDNA < mmdsDNA < FAPdU-, Pyr-dU-ddsDNA < FAP-dC-ddsDNA (K(D) = 68 +/- 1; 25 +/- 6; 13 +/- 1; 8 +/- 2, and 3.5 +/- 0.5 nM correspondingly) but weakly depends on the chain integrity. Interestingly the bulkier lesions not in all cases have a greater effect on RPA affinity to ddsDNA. The experiments on photoaffinity modification demonstrated only p70 of compactly arranged RPA directly interacting with dsDNA. The formation of RPA-ddsDNA covalent adducts was drastically reduced when both strands of DNA duplex contained virtually opposite located FAP-dC and Antr-dC. Thus RPA requires undamaged DNA strand presence for the effective interaction with dsDNA bearing bulky damages and demonstrates the early NER factors characteristic features underlying strand discrimination capacity and poor activity of the NER system toward double damaged DNA.
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Affiliation(s)
- Irina O Petruseva
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, pr. Lavrentieva, 8, Novosibirsk 630090, Russia
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Mou TC, Shen M, Abdalla S, Delamora D, Bochkareva E, Bochkarev A, Gray DM. Effects of ssDNA sequences on non-sequence-specific protein binding. Chirality 2007; 18:370-82. [PMID: 16575881 DOI: 10.1002/chir.20262] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The circular dichroism (CD) spectra of single-stranded DNAs (ssDNAs) are significantly perturbed by the binding of single-stranded DNA binding proteins such as the Ff bacteriophage gene 5 protein (g5p) and the A domain of the 70 kDa subunit of human replication protein A (RPA70-A). These two proteins have similar OB-fold secondary structures, although their CD spectra at wavelengths below 250 nm differ greatly. The spectrum of g5p is dominated by a tyrosyl L(a) band at 229 nm, while that of RPA70-A is dominated by its beta secondary structure. Despite differences in their inherent spectral properties, these two proteins similarly perturb the spectra of bound nucleic acid oligomers. CD spectra of free, non-protein-bound ssDNAs are dependent on interactions of the nearest-neighboring nucleotides in the sequence. The CD spectra (per mol of nucleotide) of simple repetitive sequences 48 nucleotides in length and containing simple combinations of A and C are related by nearest-neighbor equations. For example, 3 x Deltaepsilon[d(AAC)(16)] = 3 x Deltaepsilon[d(ACC)(16)] + Deltaepsilon[d(A)(48)] - Deltaepsilon[d(C)(48)]. Moreover, nearest-neighbor equations relate the spectra of ssDNAs when they are bound by g5p, indicating that each type of perturbed nearest neighbor has a similar average structure within the binding site of the protein.
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Affiliation(s)
- Tung-Chung Mou
- Department of Biochemistry, The University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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Fanning E, Klimovich V, Nager AR. A dynamic model for replication protein A (RPA) function in DNA processing pathways. Nucleic Acids Res 2006; 34:4126-37. [PMID: 16935876 PMCID: PMC1616954 DOI: 10.1093/nar/gkl550] [Citation(s) in RCA: 435] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Processing of DNA in replication, repair and recombination pathways in cells of all organisms requires the participation of at least one major single-stranded DNA (ssDNA)-binding protein. This protein protects ssDNA from nucleolytic damage, prevents hairpin formation and blocks DNA reannealing until the processing pathway is successfully completed. Many ssDNA-binding proteins interact physically and functionally with a variety of other DNA processing proteins. These interactions are thought to temporally order and guide the parade of proteins that 'trade places' on the ssDNA, a model known as 'hand-off', as the processing pathway progresses. How this hand-off mechanism works remains poorly understood. Recent studies of the conserved eukaryotic ssDNA-binding protein replication protein A (RPA) suggest a novel mechanism by which proteins may trade places on ssDNA by binding to RPA and mediating conformation changes that alter the ssDNA-binding properties of RPA. This article reviews the structure and function of RPA, summarizes recent studies of RPA in DNA replication and other DNA processing pathways, and proposes a general model for the role of RPA in protein-mediated hand-off.
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Affiliation(s)
- Ellen Fanning
- Department of Biological Sciences, Vanderbilt University, VU Station B 351634, Nashville, TN 37235-1634, USA.
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Nasheuer HP, Pospiech H, Syväoja J. Progress Towards the Anatomy of the Eukaryotic DNA Replication Fork. Genome Integr 2006. [DOI: 10.1007/7050_016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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Liu Y, Kvaratskhelia M, Hess S, Qu Y, Zou Y. Modulation of replication protein A function by its hyperphosphorylation-induced conformational change involving DNA binding domain B. J Biol Chem 2005; 280:32775-83. [PMID: 16006651 PMCID: PMC1450107 DOI: 10.1074/jbc.m505705200] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human replication protein A (RPA), composed of RPA70, RPA32, and RPA14 subunits, undergoes hyperphosphorylation in cells in response to DNA damage. Hyperphosphorylation that occurs predominately in the N-terminal region of RPA32 is believed to play a role in modulating the cellular activities of RPA essential for almost all DNA metabolic pathways. To understand how the hyperphosphorylation modulates the functions of RPA, we compared the structural characteristics of full-length native and hyperphosphorylated RPAs using mass spectrometric protein footprinting, fluorescence spectroscopy, and limited proteolysis. Our mass spectrometric data showed that of 24 lysines and 18 arginines readily susceptible to small chemical reagent modification in native RPA, the three residues Lys-343, Arg-335, and Arg-382, located in DNA binding domain B (DBD-B) of RPA70, were significantly shielded in the hyperphosphorylated protein. Tryptophan fluorescence studies indicated significant quenching of Trp-361, located in the DBD-B domain, induced by hyperphosphorylation of RPA. Consistently, DBD-B became more resistant to the limited proteolysis by chymotrypsin after RPA hyperphosphorylation. Taken together, our results indicate that upon hyperphosphorylation of RPA32 N terminus (RPA32N), RPA undergoes a conformational change involving the single-stranded DNA binding cleft of DBD-B. Comparison of the interactions of native and hyperphosphorylated RPAs with short single-stranded oligonucleotides or partial DNA duplexes with a short 5' or 3' single-stranded DNA tails showed reduced affinity for the latter protein. We propose that the hyperphosphorylation may play a role in modulating the cellular pathways by altering the DBD-B-mediated RPA-DNA and RPA-protein interactions, hypothetically via the interaction of hyperphosphorylated RPA32N with DBD-B.
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Affiliation(s)
- Yiyong Liu
- Department of Biochemistry and Molecular Biology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614, USA
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Highly efficient modification of DNA polymerase β under conditions of direct and sensitized activation of photoreactive DNAs. Modification of cell extract proteins. Russ Chem Bull 2005. [DOI: 10.1007/s11172-005-0400-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Weisshart K, Pestryakov P, Smith RWP, Hartmann H, Kremmer E, Lavrik O, Nasheuer HP. Coordinated regulation of replication protein A activities by its subunits p14 and p32. J Biol Chem 2004; 279:35368-76. [PMID: 15205463 DOI: 10.1074/jbc.m403825200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The heterotrimeric replication protein A (RPA) has multiple essential activities in eukaryotic DNA metabolism and in signaling pathways. Despite extensive analyses, the functions of the smallest RPA subunit p14 are still unknown. To solve this issue we produced and characterized a dimeric RPA complex lacking p14, RPADeltap14, consisting of p70 and p32. RPADeltap14 was able to bind single-stranded DNA, but its binding mode and affinity differed from those of the heterotrimeric complex. Moreover, in the RPADeltap14 complex p32 only minimally recognized the 3'-end of a primer in a primer-template junction. Partial proteolytic digests revealed that p14 and p32 together stabilize the C terminus of p70 against degradation. Although RPADeltap14 efficiently supported bidirectional unwinding of double-stranded DNA and interacted with both the simian virus 40 (SV40) large T antigen and cellular DNA polymerase alpha-primase, it did not support cell-free SV40 DNA replication. This inability manifested itself in a failure to support both the primer synthesis and primer elongation reactions. These data reveal that efficient binding and correct positioning of the RPA complex on single-stranded DNA requires all three subunits to support DNA replication.
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Affiliation(s)
- Klaus Weisshart
- Institute of Molecular Biotechnology, Beutenbergstrasse 11, Jena 07745, Germany
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Pestryakov PE, Khlimankov DY, Bochkareva E, Bochkarev A, Lavrik OI. Human replication protein A (RPA) binds a primer-template junction in the absence of its major ssDNA-binding domains. Nucleic Acids Res 2004; 32:1894-903. [PMID: 15047856 PMCID: PMC390355 DOI: 10.1093/nar/gkh346] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The human nuclear single-stranded (ss) DNA- binding protein, replication protein A (RPA), is a heterotrimer consisting of three subunits: p70, p32 and p14. The protein-DNA interaction is mediated by several DNA-binding domains (DBDs): two major (A and B, also known as p70A and p70B) and several minor (C and D, also known as p70C and p32D, and, presumably, by p70N). Here, using crosslinking experiments, we investigated an interaction of RPA deletion mutants containing a subset of the DBDs with partial DNA duplexes containing 5'-protruding ssDNA tails of 10, 20 and 30 nt. The crosslinks were generated using either a 'zero-length' photoreactive group (4-thio-2'-deoxyuridine-5'-monophosphate) embedded in the 3' end of the DNA primer, or a group connected to the 3' end by a lengthy linker (5-[N-[N-(4-azido-2,5-difluoro-3- chloropyridine-6-yl)-3-aminopropionyl]-trans-3-aminopropenyl-1]-2'-deoxyuridine-5'-monophosphate). In the absence of two major DBDs, p70A and p70B, the RPA trimerization core (p70C.p32D.p14) was capable of correctly recognizing the primer- template junction and adopting an orientation similar to that in native RPA. Both p70C and p32D contributed to this recognition. However, the domain contribution differed depending on the size of the ssDNA. In contrast with the trimerization core, the RPA dimerization core (p32D.p14) was incapable of detectably recognizing the DNA- junction structures, suggesting an orchestrating role for p70C in this process.
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Affiliation(s)
- Pavel E Pestryakov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Prospect Lavrentieva 8, 630090, Novosibirsk, Russia
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Kaufmann G, Nethanel T. Did an early version of the eukaryal replisome enable the emergence of chromatin? PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2004; 77:173-209. [PMID: 15196893 DOI: 10.1016/s0079-6603(04)77005-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Gabriel Kaufmann
- Biochemistry Department, Tel Aviv University, Ramat Aviv 69978, Israel
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Pestryakov PE, Weisshart K, Schlott B, Khodyreva SN, Kremmer E, Grosse F, Lavrik OI, Nasheuer HP. Human replication protein A. The C-terminal RPA70 and the central RPA32 domains are involved in the interactions with the 3'-end of a primer-template DNA. J Biol Chem 2003; 278:17515-24. [PMID: 12600993 DOI: 10.1074/jbc.m301265200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although the mechanical aspects of the single-stranded DNA (ssDNA) binding activity of human replication protein A (RPA) have been extensively studied, only limited information is available about its interaction with other physiologically relevant DNA structures. RPA interacts with partial DNA duplexes that resemble DNA intermediates found in the processes of DNA replication and DNA repair. Limited proteolysis of RPA showed that RPA associated with ssDNA is less protected against proteases than RPA bound to a partial duplex DNA containing a 5'-protruding tail that had the same length as the ssDNA. Modification of both the 70- and 32-kDa subunits, RPA70 and RPA32, respectively, by photoaffinity labeling indicates that RPA can bind the primer-template junction of partial duplex DNAs by interacting with the 3'-end of the primer. The identification of the protein domains modified by the photoreactive 3'-end of the primer showed that domains located in the central part of the RPA32 subunit (amino acids 39-180) and the C-terminal part of the RPA70 subunit (amino acids 432-616) are involved in these interactions.
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Affiliation(s)
- Pavel E Pestryakov
- Abteilung Biochemie, Institut für Molekulare Biotechnologie, D-07745 Jena, Germany
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Lavrik OI, Kolpashchikov DM, Prasad R, Sobol RW, Wilson SH. Binary system for selective photoaffinity labeling of base excision repair DNA polymerases. Nucleic Acids Res 2002; 30:e73. [PMID: 12136121 PMCID: PMC135774 DOI: 10.1093/nar/gnf073] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A system of photoaffinity reagents for selective labeling of DNA polymerases in extracts has been examined. To create the photoreactive DNA probe in situ, DNA substrates containing a synthetic abasic site are incubated in mouse embryonic fibroblast (MEF) cellular extract in the presence of base-substituted arylazido derivatives of dNTPs. This results in synthesis of a photoreactive long patch base excision repair (BER) intermediate. The arylazido photoreactive group is then activated through energy transfer from the pyrene group of a dNTP analog (Pyr-dUTP), following 365 nm UV light exposure. Pyr-dUTP binds to the active site of DNA polymerases, and the pyrene group, when excited by 365 nm UV light, activates the nearby photoreactive group in the BER intermediate resulting in crosslinking of DNA-bound DNA polymerases. Under these conditions, various DNA binding proteins that are unable to bind Pyr-dUTP are not crosslinked to DNA. DNA polymerase beta is the predominant crosslinked protein observed in the MEF extract. In contrast, several other DNA binding proteins are labeled under conditions of direct UV light activation of the photoreactive group at 312 nm. This study illustrates use of a new method of selective labeling of DNA polymerases in a crude cellular extract.
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Affiliation(s)
- Olga I Lavrik
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Bochkareva E, Korolev S, Lees-Miller SP, Bochkarev A. Structure of the RPA trimerization core and its role in the multistep DNA-binding mechanism of RPA. EMBO J 2002; 21:1855-63. [PMID: 11927569 PMCID: PMC125950 DOI: 10.1093/emboj/21.7.1855] [Citation(s) in RCA: 251] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2001] [Revised: 01/28/2002] [Accepted: 02/08/2002] [Indexed: 11/13/2022] Open
Abstract
The human single-stranded DNA-binding protein, replication protein A (RPA) binds DNA in at least two different modes: initial [8-10 nucleotides (nt)] and stable ( approximately 30 nt). Switching from 8 to 30 nt mode is associated with a large conformational change. Here we report the 2.8 A structure of the RPA trimerization core comprising the C-terminal DNA-binding domain of subunit RPA70 (DBD-C), the central DNA-binding domain of subunit RPA32 (DBD-D) and the entire RPA14 subunit. All three domains are built around a central oligonucleotide/oligosaccharide binding (OB)-fold and flanked by a helix at the C-terminus. Trimerization is mediated by three C-terminal helices arranged in parallel. The OB-fold of DBD-C possesses unique structural features; embedded zinc ribbon and helix-turn-helix motifs. Using time-resolved proteolysis with trypsin, we demonstrate that the trimerization core does not contribute to the binding with substrates of 10 nt, but interacts with oligonucleotides of 24 nt. Taken together, our data indicate that switching from 8-10 to 30 nt mode is mediated by DNA binding with the trimerization core.
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Affiliation(s)
| | - Sergey Korolev
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190,
Structural Biology Center, Argonne National Laboratory, Argonne, IL 60439, USA and Department of Biological Sciences, University of Calgary, Alberta, Canada Corresponding author e-mail:
| | - Susan P. Lees-Miller
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190,
Structural Biology Center, Argonne National Laboratory, Argonne, IL 60439, USA and Department of Biological Sciences, University of Calgary, Alberta, Canada Corresponding author e-mail:
| | - Alexey Bochkarev
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190,
Structural Biology Center, Argonne National Laboratory, Argonne, IL 60439, USA and Department of Biological Sciences, University of Calgary, Alberta, Canada Corresponding author e-mail:
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