1
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Park J, Youn HS, An JY, Lee Y, Eom SH, Wang J. Structure of New Binary and Ternary DNA Polymerase Complexes From Bacteriophage RB69. Front Mol Biosci 2021; 8:704813. [PMID: 34869578 PMCID: PMC8639217 DOI: 10.3389/fmolb.2021.704813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 09/30/2021] [Indexed: 11/29/2022] Open
Abstract
DNA polymerase plays a critical role in passing the genetic information of any living organism to its offspring. DNA polymerase from enterobacteria phage RB69 (RB69pol) has both polymerization and exonuclease activities and has been extensively studied as a model system for B-family DNA polymerases. Many binary and ternary complex structures of RB69pol are known, and they all contain a single polymerase-primer/template (P/T) DNA complex. Here, we report a crystal structure of the exonuclease-deficient RB69pol with the P/T duplex in a dimeric form at a resolution of 2.2 Å. The structure includes one new closed ternary complex with a single divalent metal ion bound and one new open binary complex in the pre-insertion state with a vacant dNTP-binding pocket. These complexes suggest that initial binding of the correct dNTP in the open state is much weaker than expected and that initial binding of the second divalent metal ion in the closed state is also much weaker than measured. Additional conformational changes are required to convert these complexes to high-affinity states. Thus, the measured affinities for the correct incoming dNTP and divalent metal ions are average values from many conformationally distinctive states. Our structure provides new insights into the order of the complex assembly involving two divalent metal ions. The biological relevance of specific interactions observed between one RB69pol and the P/T duplex bound to the second RB69pol observed within this dimeric complex is discussed.
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Affiliation(s)
- Jongseo Park
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea.,Steitz Center for Structural Biology, GIST, Gwangju, South Korea
| | - Hyung-Seop Youn
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea.,Steitz Center for Structural Biology, GIST, Gwangju, South Korea.,BIO R&D Center, Ingredient Business Unit, Daesang Corporation, Gyeonggi-do, Korea
| | - Jun Yop An
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea.,Steitz Center for Structural Biology, GIST, Gwangju, South Korea.,Virocure Inc., Seoul, Korea
| | - Youngjin Lee
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea.,Steitz Center for Structural Biology, GIST, Gwangju, South Korea.,Metabolic Regulation Research Center, Korea Research Institute of BIoscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Soo Hyun Eom
- School of Life Sciences, Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea.,Steitz Center for Structural Biology, GIST, Gwangju, South Korea.,Department of Chemistry, GIST, Gwangju, Korea
| | - Jimin Wang
- Steitz Center for Structural Biology, GIST, Gwangju, South Korea.,Department of Molecular Biophysics and Biochemistry, New Haven, CT, United States
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2
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Liu X, Zou X, Li H, Zou Z, Yang J, Wang C, Wu S, Zhang H. Bypass of an Abasic Site via the A-Rule by DNA Polymerase of Pseudomonas aeruginosa Phage PaP1. Chem Res Toxicol 2017; 31:58-65. [PMID: 29183115 DOI: 10.1021/acs.chemrestox.7b00287] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xiaoying Liu
- School
of Public Health, Xinjiang Medical University, Urumqi 830011, China
- Public
Health Laboratory Sciences and Toxicology, West China School of Public
Health, Sichuan University, Chengdu 610041, China
| | - Xiaoli Zou
- Public
Health Laboratory Sciences and Toxicology, West China School of Public
Health, Sichuan University, Chengdu 610041, China
| | - Huangyuan Li
- Key
Laboratory of Environment and Health among Universities and Colleges
in Fujian, School of Public Health, Fujian Medical University, Minhou
County, Fuzhou 350108, China
| | - Zhenyu Zou
- Public
Health Laboratory Sciences and Toxicology, West China School of Public
Health, Sichuan University, Chengdu 610041, China
| | - Jie Yang
- Public
Health Laboratory Sciences and Toxicology, West China School of Public
Health, Sichuan University, Chengdu 610041, China
| | - Chenlu Wang
- School
of Public Health, Xinjiang Medical University, Urumqi 830011, China
| | - Shunhua Wu
- School
of Public Health, Xinjiang Medical University, Urumqi 830011, China
| | - Huidong Zhang
- Public
Health Laboratory Sciences and Toxicology, West China School of Public
Health, Sichuan University, Chengdu 610041, China
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3
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Gu S, Xiong J, Shi Y, You J, Zou Z, Liu X, Zhang H. Error-prone bypass of O 6-methylguanine by DNA polymerase of Pseudomonas aeruginosa phage PaP1. DNA Repair (Amst) 2017. [PMID: 28651167 DOI: 10.1016/j.dnarep.2017.06.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
O6-Methylguanine (O6-MeG) is highly mutagenic and is commonly found in DNA exposed to methylating agents, generally leads to G:C to A:T mutagenesis. To study DNA replication encountering O6-MeG by the DNA polymerase (gp90) of P. aeruginosa phage PaP1, we analyzed steady-state and pre-steady-state kinetics of nucleotide incorporation opposite O6-MeG by gp90 exo-. O6-MeG partially inhibited full-length extension by gp90 exo-. O6-MeG greatly reduces dNTP incorporation efficiency, resulting in 67-fold preferential error-prone incorporation of dTTP than dCTP. Gp90 exo- extends beyond T:O6-MeG 2-fold more efficiently than C:O6-MeG. Incorporation of dCTP opposite G and incorporation of dCTP or dTTP opposite O6-MeG show fast burst phases. The pre-steady-state incorporation efficiency (kpol/Kd,dNTP) is decreased in the order of dCTP:G>dTTP:O6-MeG>dCTP:O6-MeG. The presence of O6-MeG at template does not affect the binding affinity of polymerase to DNA but it weakened their binding in the presence of dCTP and Mg2+. Misincorporation of dTTP opposite O6-MeG further weakens the binding affinity of polymerase to DNA. The priority of dTTP incorporation opposite O6-MeG is originated from the fact that dTTP can induce a faster conformational change step and a faster chemical step than dCTP. This study reveals that gp90 bypasses O6-MeG in an error-prone manner and provides further understanding in DNA replication encountering mutagenic alkylation DNA damage for P. aeruginosa phage PaP1.
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Affiliation(s)
- Shiling Gu
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Jingyuan Xiong
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Ying Shi
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Jia You
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Zhenyu Zou
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Xiaoying Liu
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China
| | - Huidong Zhang
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, Chengdu, China.
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4
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A Comparative Analysis of Translesion DNA Synthesis Catalyzed by a High-Fidelity DNA Polymerase. J Mol Biol 2017; 429:2308-2323. [PMID: 28601494 DOI: 10.1016/j.jmb.2017.06.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 11/20/2022]
Abstract
Translesion DNA synthesis (TLS) is the ability of DNA polymerases to incorporate nucleotides opposite and beyond damaged DNA. TLS activity is an important risk factor for the initiation and progression of genetic diseases such as cancer. In this study, we evaluate the ability of a high-fidelity DNA polymerase to perform TLS with 8-oxo-guanine (8-oxo-G), a highly pro-mutagenic DNA lesion formed by reactive oxygen species. Results of kinetic studies monitoring the incorporation of modified nucleotide analogs demonstrate that the binding affinity of the incoming dNTP is controlled by the overall hydrophobicity of the nucleobase. However, the rate constant for the polymerization step is regulated by hydrogen-bonding interactions made between the incoming nucleotide with 8-oxo-G. Results generated here for replicating the miscoding 8-oxo-G are compared to those published for the replication of the non-instructional abasic site. During the replication of both lesions, binding of the nucleotide substrate is controlled by energetics associated with nucleobase desolvation, whereas the rate constant for the polymerization step is influenced by the physical nature of the DNA lesion, that is, miscoding versus non-instructional. Collectively, these studies highlight the importance of nucleobase desolvation as a key physical feature that enhances the misreplication of structurally diverse DNA lesions.
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5
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Gu S, Xue Q, Liu Q, Xiong M, Wang W, Zhang H. Error-Free Bypass of 7,8-dihydro-8-oxo-2'-deoxyguanosineby DNA Polymerase of Pseudomonas aeruginosa Phage PaP1. Genes (Basel) 2017; 8:genes8010018. [PMID: 28067844 PMCID: PMC5295013 DOI: 10.3390/genes8010018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 12/26/2016] [Accepted: 12/30/2016] [Indexed: 12/16/2022] Open
Abstract
As one of the most common forms of oxidative DNA damage, 7,8-dihydro-8-oxo-2′-deoxyguanosine (8-oxoG) generally leads to G:C to T:A mutagenesis. To study DNA replication encountering 8-oxoG by the sole DNA polymerase (Gp90) of Pseudomonasaeruginosa phage PaP1, we performed steady-state and pre-steady-state kinetic analyses of nucleotide incorporation opposite 8-oxoG by Gp90 D234A that lacks exonuclease activities on ssDNA and dsDNA substrates. Gp90 D234A could bypass 8-oxoG in an error-free manner, preferentially incorporate dCTP opposite 8-oxoG, and yield similar misincorporation frequency to unmodified G. Gp90 D234A could extend beyond C:8-oxoG or A:8-oxoG base pairs with the same efficiency. dCTP incorporation opposite G and dCTP or dATP incorporation opposite 8-oxoG showed fast burst phases. The burst of incorporation efficiency (kpol/Kd,dNTP) is decreased as dCTP:G > dCTP:8-oxoG > dATP:8-oxoG. The presence of 8-oxoG in DNA does not affect its binding to Gp90 D234A in a binary complex but it does affect it in a ternary complex with dNTP and Mg2+, and dATP misincorporation opposite 8-oxoG further weakens the binding of Gp90 D234A to DNA. This study reveals Gp90 D234A can bypass 8-oxoG in an error-free manner, providing further understanding in DNA replication encountering oxidation lesion for P.aeruginosa phage PaP1.
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Affiliation(s)
- Shiling Gu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China.
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China.
| | - Qizhen Xue
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China.
| | - Qin Liu
- College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China.
| | - Mei Xiong
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China.
| | - Wanneng Wang
- College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China.
| | - Huidong Zhang
- Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China.
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6
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Raper AT, Gadkari VV, Maxwell BA, Suo Z. Single-Molecule Investigation of Response to Oxidative DNA Damage by a Y-Family DNA Polymerase. Biochemistry 2016; 55:2187-96. [PMID: 27002236 DOI: 10.1021/acs.biochem.6b00166] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Y-family DNA polymerases are known to bypass DNA lesions in vitro and in vivo and rescue stalled DNA replication machinery. Dpo4, a well-characterized model Y-family DNA polymerase, is known to catalyze translesion synthesis across a variety of DNA lesions including 8-oxo-7,8-dihydro-2'-deoxyguanine (8-oxo-dG). Our previous X-ray crystallographic, stopped-flow Förster resonance energy transfer (FRET), and computational simulation studies have revealed that Dpo4 samples a variety of global conformations as it recognizes and binds DNA. Here we employed single-molecule FRET (smFRET) techniques to investigate the kinetics and conformational dynamics of Dpo4 when it encountered 8-oxo-dG, a major oxidative lesion with high mutagenic potential. Our smFRET data indicated that Dpo4 bound the DNA substrate in multiple conformations, as suggested by three observed FRET states. An incoming correct or incorrect nucleotide affected the distribution and stability of these states with the correct nucleotide completely shifting the equilibrium toward a catalytically competent complex. Furthermore, the presence of the 8-oxo-dG lesion in the DNA stabilized both the binary and ternary complexes of Dpo4. Thus, our smFRET analysis provided a basis for the enhanced efficiency which Dpo4 is known to exhibit when replicating across from 8-oxo-dG.
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Affiliation(s)
- Austin T Raper
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Varun V Gadkari
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Brian A Maxwell
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
| | - Zucai Suo
- Department of Chemistry and Biochemistry, †Ohio State Biochemistry Program and ‡Ohio State Biophysics Program, The Ohio State University , Columbus, Ohio 43210, United States
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7
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Ganai RA, Osterman P, Johansson E. Yeast DNA polymerase ϵ catalytic core and holoenzyme have comparable catalytic rates. J Biol Chem 2014; 290:3825-35. [PMID: 25538242 DOI: 10.1074/jbc.m114.615278] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The holoenzyme of yeast DNA polymerase ϵ (Pol ϵ) consists of four subunits: Pol2, Dpb2, Dpb3, and Dpb4. A protease-sensitive site results in an N-terminal proteolytic fragment of Pol2, called Pol2core, that consists of the catalytic core of Pol ϵ and retains both polymerase and exonuclease activities. Pre-steady-state kinetics showed that the exonuclease rates on single-stranded, double-stranded, and mismatched DNA were comparable between Pol ϵ and Pol2core. Single-turnover pre-steady-state kinetics also showed that the kpol of Pol ϵ and Pol2core were comparable when preloading the polymerase onto the primer-template before adding Mg(2+) and dTTP. However, a global fit of the data over six sequential nucleotide incorporations revealed that the overall polymerization rate and processivity were higher for Pol ϵ than for Pol2core. The largest difference between Pol ϵ and Pol2core was observed when challenged for the formation of a ternary complex and incorporation of the first nucleotide. Pol ϵ needed less than 1 s to incorporate a nucleotide, but several seconds passed before Pol2core incorporated detectable levels of the first nucleotide. We conclude that the accessory subunits and the C terminus of Pol2 do not influence the catalytic rate of Pol ϵ but facilitate the loading and incorporation of the first nucleotide by Pol ϵ.
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Affiliation(s)
- Rais A Ganai
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Pia Osterman
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
| | - Erik Johansson
- From the Department of Medical Biochemistry and Biophysics, Umeå University, SE-901 87 Umeå, Sweden
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8
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Eckenroth BE, Fleming AM, Sweasy JB, Burrows CJ, Doublié S. Crystal structure of DNA polymerase β with DNA containing the base lesion spiroiminodihydantoin in a templating position. Biochemistry 2014; 53:2075-7. [PMID: 24649945 PMCID: PMC3985455 DOI: 10.1021/bi500270e] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The
first high-resolution crystal structure of spiroiminodihydantoin
(dSp1) was obtained in the context of the DNA polymerase β active
site and reveals two areas of significance. First, the structure verifies
the recently determined S configuration at the spirocyclic
carbon. Second, the distortion of the DNA duplex is similar to that
of the single-oxidation product 8-oxoguanine. For both oxidized lesions,
adaptation of the syn conformation results in similar
backbone distortions in the DNA duplex. The resulting conformation
positions the dSp1 A-ring as the base-pairing face whereas the B-ring
of dSp1 protrudes into the major groove.
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Affiliation(s)
- Brian E Eckenroth
- Department of Microbiology and Molecular Genetics, University of Vermont , Stafford Hall, 95 Carrigan Drive, Burlington, Vermont 05405, United States
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9
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Jacewicz A, Trzemecka A, Guja KE, Plochocka D, Yakubovskaya E, Bebenek A, Garcia-Diaz M. A remote palm domain residue of RB69 DNA polymerase is critical for enzyme activity and influences the conformation of the active site. PLoS One 2013; 8:e76700. [PMID: 24116139 PMCID: PMC3792054 DOI: 10.1371/journal.pone.0076700] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/23/2013] [Indexed: 11/26/2022] Open
Abstract
Non-conserved amino acids that are far removed from the active site can sometimes have an unexpected effect on enzyme catalysis. We have investigated the effects of alanine replacement of residues distant from the active site of the replicative RB69 DNA polymerase, and identified a substitution in a weakly conserved palm residue (D714A), that renders the enzyme incapable of sustaining phage replication in vivo. D714, located several angstroms away from the active site, does not contact the DNA or the incoming dNTP, and our apoenzyme and ternary crystal structures of the PolD714A mutant demonstrate that D714A does not affect the overall structure of the protein. The structures reveal a conformational change of several amino acid side chains, which cascade out from the site of the substitution towards the catalytic center, substantially perturbing the geometry of the active site. Consistent with these structural observations, the mutant has a significantly reduced kpol for correct incorporation. We propose that the observed structural changes underlie the severe polymerization defect and thus D714 is a remote, non-catalytic residue that is nevertheless critical for maintaining an optimal active site conformation. This represents a striking example of an action-at-a-distance interaction.
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Affiliation(s)
- Agata Jacewicz
- Department of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Anna Trzemecka
- Department of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Kip E. Guja
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Danuta Plochocka
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Elena Yakubovskaya
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
| | - Anna Bebenek
- Department of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- * E-mail: (AB); (MGD)
| | - Miguel Garcia-Diaz
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail: (AB); (MGD)
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10
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Utility of the bacteriophage RB69 polymerase gp43 as a surrogate enzyme for herpesvirus orthologs. Viruses 2013; 5:54-86. [PMID: 23299784 PMCID: PMC3564110 DOI: 10.3390/v5010054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 12/16/2012] [Accepted: 12/17/2012] [Indexed: 01/09/2023] Open
Abstract
Viral polymerases are important targets in drug discovery and development efforts. Most antiviral compounds that are currently approved for treatment of infection with members of the herpesviridae family were shown to inhibit the viral DNA polymerase. However, biochemical studies that shed light on mechanisms of drug action and resistance are hampered primarily due to technical problems associated with enzyme expression and purification. In contrast, the orthologous bacteriophage RB69 polymerase gp43 has been crystallized in various forms and therefore serves as a model system that provides a better understanding of structure–function relationships of polymerases that belong the type B family. This review aims to discuss strengths, limitations, and opportunities of the phage surrogate with emphasis placed on its utility in the discovery and development of anti-herpetic drugs.
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11
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Freudenthal BD, Beard WA, Wilson SH. DNA polymerase minor groove interactions modulate mutagenic bypass of a templating 8-oxoguanine lesion. Nucleic Acids Res 2012; 41:1848-58. [PMID: 23267011 PMCID: PMC3561998 DOI: 10.1093/nar/gks1276] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A major base lesion resulting from oxidative stress is 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxoG) that has ambiguous coding potential. Error-free DNA synthesis involves 8-oxoG adopting an anti-conformation to base pair with cytosine whereas mutagenic bypass involves 8-oxoG adopting a syn-conformation to base pair with adenine. Left unrepaired the syn-8-oxoG/dAMP base pair results in a G–C to T–A transversion. During base excision repair of this mispair, DNA polymerase (pol) β is confronted with gap filling opposite 8-oxoG. To determine how pol β discriminates between anti- and syn-8-oxoG, we introduced a point mutation (R283K) to alter insertion specificity. Kinetic studies demonstrate that this substitution results in an increased fidelity opposite 8-oxoG. Structural studies with R283K pol β show that the binary DNA complex has 8-oxoG in equilibrium between anti- and syn-forms. Ternary complexes with incoming dCTP resemble the wild-type enzyme, with templating anti-8-oxoG base pairing with incoming cytosine. In contrast to wild-type pol β, the ternary complex of the R283K mutant with an incoming dATP-analogue and templating 8-oxoG resembles a G–A mismatched structure with 8-oxoG adopting an anti-conformation. These results demonstrate that the incoming nucleotide is unable to induce a syn-8-oxoG conformation without minor groove DNA polymerase interactions that influence templating (anti-/syn-equilibrium) of 8-oxoG while modulating fidelity.
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Affiliation(s)
- Bret D Freudenthal
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, PO Box 12233, Research Triangle Park, NC 27709-2233, USA
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12
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Maxwell BA, Suo Z. Kinetic basis for the differing response to an oxidative lesion by a replicative and a lesion bypass DNA polymerase from Sulfolobus solfataricus. Biochemistry 2012; 51:3485-96. [PMID: 22471521 DOI: 10.1021/bi300246r] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
8-Oxo-7,8-dihydro-2'-deoxyguanine (8-oxoG), a major oxidative DNA lesion, exhibits ambiguous coding potential and can lead to genomic mutations. Tight control of 8-oxoG bypass during DNA replication is therefore extremely important in hyperthermophiles as the rate of oxidative damage to DNA is significantly increased at high temperatures. Here we employed pre-steady state kinetics to compare the kinetic responses to an 8-oxoG lesion of the main replicative and lesion bypass DNA polymerases of Sulfolobus solfataricus, a hyperthermophilic crenarchaeon. Upon encountering 8-oxoG, PolB1, the replicative DNA polymerase, was completely stalled by the lesion, as its 3' → 5' exonuclease activity increased significantly and outcompeted its slowed polymerase activity at and near the lesion site. In contrast, our results show that Dpo4, the lone Y-family DNA polymerase in S. solfataricus, can faithfully and efficiently incorporate nucleotides opposite 8-oxoG and extend from an 8-oxoG:C base pair with a mechanism similar to that observed for the replication of undamaged DNA. Furthermore, we show that the stalling of PolB1 at the lesion site can be relieved by Dpo4. Finally, the 3' → 5' exonuclease activity of PolB1 was the highest when 8-oxoG was mispaired with an incorrect nucleotide and could therefore correct rare mistakes made by Dpo4 during 8-oxoG bypass. These results provide a kinetic basis for a potential polymerase switching mechanism during 8-oxoG bypass whereby Dpo4 can switch with the stalled PolB1 at the replication fork to bypass and extend the damaged DNA and then switch off of the DNA substrate to allow continued replication of undamaged DNA by the more faithful PolB1.
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Affiliation(s)
- Brian A Maxwell
- Ohio State Biophysics Program and Department of Biochemistry, The Ohio State University, Columbus, OH 43210, USA
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13
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Loakes D. Nucleotides and nucleic acids; oligo- and polynucleotides. ORGANOPHOSPHORUS CHEMISTRY 2012. [DOI: 10.1039/9781849734875-00169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- David Loakes
- Medical Research Council Laboratory of Molecular Biology, Hills Road Cambridge CB2 2QH UK
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14
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Binary complex crystal structure of DNA polymerase β reveals multiple conformations of the templating 8-oxoguanine lesion. Proc Natl Acad Sci U S A 2011; 109:113-8. [PMID: 22178760 DOI: 10.1073/pnas.1112235108] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Oxidation of genomic DNA forms the guanine lesion 7,8-dihydro-8-oxoguanine (8-oxoG). When in the template base position during DNA synthesis the 8-oxoG lesion has dual coding potential by virtue of its anti- and syn-conformations, base pairing with cytosine and adenine, respectively. This impacts mutagenesis, because insertion of adenine opposite template 8-oxoG can result in a G to T transversion. DNA polymerases vary by orders of magnitude in their preferences for mutagenic vs. error-free 8-oxoG lesion bypass. Yet, the structural basis for lesion bypass specificity is not well understood. The DNA base excision repair enzyme DNA polymerase (pol) β is presented with gap-filling synthesis opposite 8-oxoG during repair and has similar insertion efficiencies for dCTP and dATP. We report the structure of pol β in binary complex with template 8-oxoG in a base excision repair substrate. The structure reveals both the syn- and anti-conformations of template 8-oxoG in the confines of the polymerase active site, consistent with the dual coding observed kinetically for this enzyme. A ternary complex structure of pol β with the syn-8-oxoG:anti-A Hoogsteen base pair in the closed fully assembled preinsertion active site is also reported. The syn-conformation of 8-oxoG is stabilized by minor groove hydrogen bonding between the side chain of Arg283 and O8 of 8-oxoG. An adjustment in the position of the phosphodiester backbone 5'-phosphate enables 8-oxoG to adopt the syn-conformation.
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Zahn KE, Averill A, Wallace SS, Doublié S. The miscoding potential of 5-hydroxycytosine arises due to template instability in the replicative polymerase active site. Biochemistry 2011; 50:10350-8. [PMID: 22026756 DOI: 10.1021/bi201219s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
5-Hydroxycytosine (5-OHC) is a stable oxidation product of cytosine associated with an increased frequency of C → T transition mutations. When this lesion escapes recognition by the base excision repair pathway and persists to serve as a templating base during DNA synthesis, replicative DNA polymerases often misincorporate dAMP at the primer terminus, which can lead to fixation of mutations and subsequent disease. To characterize the dynamics of DNA synthesis opposite 5-OHC, we initiated a comparison of unmodified dCMP to 5-OHC, 5-fluorocytosine (5-FC), and 5-methylcytosine (5-MEC) in which these bases act as templates in the active site of RB69 gp43, a high-fidelity DNA polymerase sharing homology with human replicative DNA polymerases. This study presents the first crystal structure of any DNA polymerase binding this physiologically important premutagenic DNA lesion, showing that while dGMP is stabilized by 5-OHC through normal Watson-Crick base pairing, incorporation of dAMP leads to unstacking and instability in the template. Furthermore, the electronegativity of the C5 substituent appears to be important in the miscoding potential of these cytosine-like templates. While dAMP is incorporated opposite 5-OHC ~5 times more efficiently than opposite unmodified dCMP, an elevated level of incorporation is also observed opposite 5-FC but not 5-MEC. Taken together, these data imply that the nonuniform templating by 5-OHC is due to weakened stacking capabilities, which allows dAMP incorporation to proceed in a manner similar to that observed opposite abasic sites.
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, United States
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Aller P, Duclos S, Wallace SS, Doublié S. A crystallographic study of the role of sequence context in thymine glycol bypass by a replicative DNA polymerase serendipitously sheds light on the exonuclease complex. J Mol Biol 2011; 412:22-34. [PMID: 21781974 DOI: 10.1016/j.jmb.2011.07.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2011] [Revised: 06/27/2011] [Accepted: 07/06/2011] [Indexed: 10/18/2022]
Abstract
Thymine glycol (Tg) is the most common oxidation product of thymine and is known to be a strong block to replicative DNA polymerases. A previously solved structure of the bacteriophage RB69 DNA polymerase (RB69 gp43) in complex with Tg in the sequence context 5'-G-Tg-G shed light on how Tg blocks primer elongation: The protruding methyl group of the oxidized thymine displaces the adjacent 5'-G, which can no longer serve as a template for primer elongation [Aller, P., Rould, M. A., Hogg, M, Wallace, S. S. & Doublié S. (2007). A structural rationale for stalling of a replicative DNA polymerase at the most common oxidative thymine lesion, thymine glycol. Proc. Natl. Acad. Sci. USA, 104, 814-818.]. Several studies showed that in the sequence context 5'-C-Tg-purine, Tg is more likely to be bypassed by Klenow fragment, an A-family DNA polymerase. We set out to investigate the role of sequence context in Tg bypass in a B-family polymerase and to solve the crystal structures of the bacteriophage RB69 DNA polymerase in complex with Tg-containing DNA in the three remaining sequence contexts: 5'-A-Tg-G, 5'-T-Tg-G, and 5'-C-Tg-G. A combination of several factors-including the associated exonuclease activity, the nature of the 3' and 5' bases surrounding Tg, and the cis-trans interconversion of Tg-influences Tg bypass. We also visualized for the first time the structure of a well-ordered exonuclease complex, allowing us to identify and confirm the role of key residues (Phe123, Met256, and Tyr257) in strand separation and in the stabilization of the primer strand in the exonuclease site.
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Affiliation(s)
- Pierre Aller
- Department of Microbiology andMolecular Genetics, Stafford Hall, University of Vermont, Burlington, VT 05405, USA
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Zahn KE, Tchesnokov EP, Götte M, Doublié S. Phosphonoformic acid inhibits viral replication by trapping the closed form of the DNA polymerase. J Biol Chem 2011; 286:25246-55. [PMID: 21566148 DOI: 10.1074/jbc.m111.248864] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Phosphonoformic acid (PFA, foscarnet) belongs to a class of antiviral drugs that inhibit the human cytomegalovirus DNA polymerase (UL54) by mimicking the pyrophosphate leaving group of the nucleotide transfer reaction. Difficulties expressing UL54 have hampered investigation of the precise structural requirements rendering inhibition by this drug. However, a previously engineered chimeric DNA polymerase, constructed by mutating the homologous polymerase from bacteriophage RB69 (gp43) to express several variable elements from UL54, can bypass this obstacle because of its favorable expression and acquired sensitivity to PFA (Tchesnokov, E. P., Obikhod, A., Schinazi, R. F., and Götte, M. (2008) J. Biol. Chem. 283, 34218-34228). Here, we compare two crystal structures that depict the chimeric DNA polymerase with and without PFA bound. PFA is visualized for the first time in the active site of a DNA polymerase, where interactions are resolved between the PP(i) mimic and two basic residues absolutely conserved in the fingers domain of family B polymerases. PFA also chelates metal ion B, the cation that contacts the triphosphate tail of the incoming nucleotide. These DNA complexes utilize a primer-template pair enzymatically chain-terminated by incorporation of acyclo-GMP, the phosphorylated form of the anti-herpes drug acyclovir. We postulate that the V478W mutation present in the chimera is critical in that it pushes the fingers domain to more readily adopt the closed conformation whether or not the drug is bound. The closed state of the fingers domain traps the variant polymerase in the untranslocated state and increases affinity for PFA. This finding provides a model for the mechanism of UL54 stalling by PFA.
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405, USA
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Zahn KE, Wallace SS, Doublié S. DNA polymerases provide a canon of strategies for translesion synthesis past oxidatively generated lesions. Curr Opin Struct Biol 2011; 21:358-69. [PMID: 21482102 DOI: 10.1016/j.sbi.2011.03.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 02/07/2023]
Abstract
Deducing the structure of the DNA double helix in 1953 implied the mode of its replication: Watson-Crick (WC) base pairing might instruct an enzyme, now known as the DNA polymerase, during the synthesis of a daughter stand complementary to a single strand of the parental double helix. What has become increasingly clear in the last 60 years, however, is that adducted and oxidatively generated DNA bases are ubiquitous in physiological DNA, and all organisms conserve multiple DNA polymerases specialized for DNA synthesis opposite these damaged templates. Here, we review recent crystal structures depicting replicative and bypass DNA polymerases encountering two typical lesions arising from the oxidation of DNA: abasic sites, which block the replication fork, and the miscoding premutagenic lesion 7,8-dihydro-8-oxoguanine (8-oxoG).
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Affiliation(s)
- Karl E Zahn
- Department of Microbiology and Molecular Genetics, The Markey Center for Molecular Genetics, University of Vermont, Burlington, VT 05405, USA
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