1
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Nudler E. Transcription-coupled global genomic repair in E. coli. Trends Biochem Sci 2023; 48:873-882. [PMID: 37558547 DOI: 10.1016/j.tibs.2023.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 07/17/2023] [Accepted: 07/17/2023] [Indexed: 08/11/2023]
Abstract
The nucleotide excision repair (NER) pathway removes helix-distorting lesions from DNA in all organisms. Escherichia coli has long been a model for understanding NER, which is traditionally divided into major and minor subpathways known as global genome repair (GGR) and transcription-coupled repair (TCR), respectively. TCR has been assumed to be mediated exclusively by Mfd, a DNA translocase of minimal NER phenotype. This review summarizes the evidence that shaped the traditional view of NER in bacteria, and reviews data supporting a new model in which GGR and TCR are inseparable. In this new model, RNA polymerase serves both as the essential primary sensor of bulky DNA lesions genome-wide and as the delivery platform for the assembly of functional NER complexes in living cells.
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Affiliation(s)
- Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman School of Medicine, New York, NY 10016, USA; Howard Hughes Medical Institute, New York University Grossman School of Medicine, New York, NY 10016, USA.
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2
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Carvajal-Garcia J, Samadpour AN, Hernandez Viera AJ, Merrikh H. Oxidative stress drives mutagenesis through transcription-coupled repair in bacteria. Proc Natl Acad Sci U S A 2023; 120:e2300761120. [PMID: 37364106 PMCID: PMC10318952 DOI: 10.1073/pnas.2300761120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/25/2023] [Indexed: 06/28/2023] Open
Abstract
In bacteria, mutations lead to the evolution of antibiotic resistance, which is one of the main public health problems of the twenty-first century. Therefore, determining which cellular processes most frequently contribute to mutagenesis, especially in cells that have not been exposed to exogenous DNA damage, is critical. Here, we show that endogenous oxidative stress is a key driver of mutagenesis and the subsequent development of antibiotic resistance. This is the case for all classes of antibiotics and highly divergent species tested, including patient-derived strains. We show that the transcription-coupled repair pathway, which uses the nucleotide excision repair proteins (TC-NER), is responsible for endogenous oxidative stress-dependent mutagenesis and subsequent evolution. This suggests that a majority of mutations arise through transcription-associated processes rather than the replication fork. In addition to determining that the NER proteins play a critical role in mutagenesis and evolution, we also identify the DNA polymerases responsible for this process. Our data strongly suggest that cooperation between three different mutagenic DNA polymerases, likely at the last step of TC-NER, is responsible for mutagenesis and evolution. Overall, our work identifies a highly conserved pathway that drives mutagenesis due to endogenous oxidative stress, which has broad implications for all diseases of evolution, including antibiotic resistance development.
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Affiliation(s)
- Juan Carvajal-Garcia
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN37232
| | | | | | - Houra Merrikh
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN37232
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3
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He F, Bravo M, Fan L. Helicases required for nucleotide excision repair: structure, function and mechanism. Enzymes 2023; 54:273-304. [PMID: 37945175 DOI: 10.1016/bs.enz.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Nucleotide excision repair (NER) is a major DNA repair pathway conserved from bacteria to humans. Various DNA helicases, a group of enzymes capable of separating DNA duplex into two strands through ATP binding and hydrolysis, are required by NER to unwind the DNA duplex around the lesion to create a repair bubble and for damage verification and removal. In prokaryotes, UvrB helicase is required for repair bubble formation and damage verification, while UvrD helicase is responsible for the removal of the excised damage containing single-strand (ss) DNA fragment. In addition, UvrD facilitates transcription-coupled repair (TCR) by backtracking RNA polymerase stalled at the lesion. In eukaryotes, two helicases XPB and XPD from the transcription factor TFIIH complex fulfill the helicase requirements of NER. Interestingly, homologs of all these four helicases UvrB, UvrD, XPB, and XPD have been identified in archaea. This review summarizes our current understanding about the structure, function, and mechanism of these four helicases.
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Affiliation(s)
- Feng He
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, United States
| | - Marco Bravo
- Department of Biochemistry, University of California, Riverside, CA, United States
| | - Li Fan
- Department of Biochemistry, University of California, Riverside, CA, United States.
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4
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Thakur M, Muniyappa K. Macrophage activation highlight an important role for NER proteins in the survival, latency and multiplication of Mycobacterium tuberculosis. Tuberculosis (Edinb) 2023; 138:102284. [PMID: 36459831 DOI: 10.1016/j.tube.2022.102284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/14/2022] [Accepted: 11/20/2022] [Indexed: 11/27/2022]
Abstract
Nucleotide excision repair (NER) is one of the most extensively studied DNA repair processes in both prokaryotes and eukaryotes. The NER pathway is a highly conserved, ATP-dependent multi-step process involving several proteins/enzymes that function in a concerted manner to recognize and excise a wide spectrum of helix-distorting DNA lesions and bulky adducts by nuclease cleavage on either side of the damaged bases. As such, the NER pathway of Mycobacterium tuberculosis (Mtb) is essential for its survival within the hostile environment of macrophages and disease progression. This review focuses on present published knowledge about the crucial roles of Mtb NER proteins in the survival and multiplication of the pathogen within the macrophages and as potential targets for drug discovery.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
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5
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Satusky MJ, Wilkins H, Hutson B, Nasiri M, King D, Erie DA, Freeman TC. CUREing biochemistry lab monotony. JOURNAL OF CHEMICAL EDUCATION 2022; 99:3888-3898. [PMID: 38628949 PMCID: PMC11019968 DOI: 10.1021/acs.jchemed.2c00357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/19/2024]
Abstract
Undergraduate research experience is critical to success in post-graduate research settings. The recent movement away from "cookbook" style labs to course-based undergraduate research experiences (CUREs) in undergraduate laboratories has allowed universities to provide inclusive research experience while bypassing the limitations of extracurricular apprenticeships. This paper describes an upper-level biochemistry CURE designed to provide students with an introductory experience to graduate-level research by studying a suspected DNA helicase. This CURE is designed to span multiple semesters, where each student cohort builds upon the work of previous semesters. Pre- and post-course surveys were employed to assess student confidence in bench skills, perceptions of the course, and project ownership. The results show that the incorporation of lab meeting-style recitations and poster presentations led to higher project ownership, while overcoming troubleshooting was a significant challenge. Furthermore, confidence in every experimental technique increased significantly in all but one instance. Based on these results, this CURE is providing students with a realistic experience in graduate-level research.
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Affiliation(s)
- Matthew J Satusky
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Hunter Wilkins
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Bryant Hutson
- Office of Institutional Research and Assessment, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mahfuz Nasiri
- Office of Institutional Research and Assessment, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Dillon King
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Nicholas School of the Environment, Duke University, Durham, NC 27710, USA
| | - Dorothy A. Erie
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Thomas C. Freeman
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA
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6
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Thakur M, Parulekar RS, Barale SS, Sonawane KD, Muniyappa K. Interrogating the substrate specificity landscape of UvrC reveals novel insights into its non-canonical function. Biophys J 2022; 121:3103-3125. [PMID: 35810330 PMCID: PMC9463653 DOI: 10.1016/j.bpj.2022.07.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 05/23/2022] [Accepted: 07/07/2022] [Indexed: 11/29/2022] Open
Abstract
Although it is relatively unexplored, accumulating data highlight the importance of tripartite crosstalk between nucleotide excision repair (NER), DNA replication, and recombination in the maintenance of genome stability; however, elucidating the underlying mechanisms remains challenging. While Escherichia coli uvrA and uvrB can fully complement polAΔ cells in DNA replication, uvrC attenuates this alternative DNA replication pathway, but the exact mechanism by which uvrC suppresses DNA replication is unknown. Furthermore, the identity of bona fide canonical and non-canonical substrates for UvrCs are undefined. Here, we reveal that Mycobacterium tuberculosis UvrC (MtUvrC) strongly binds to, and robustly cleaves, key intermediates of DNA replication/recombination as compared with the model NER substrates. Notably, inactivation of MtUvrC ATPase activity significantly attenuated its endonuclease activity, thus suggesting a causal link between these two functions. We built an in silico model of the interaction of MtUvrC with the Holliday junction (HJ), using a combination of homology modeling, molecular docking, and molecular dynamic simulations. The model predicted residues that were potentially involved in HJ binding. Six of these residues were mutated either singly or in pairs, and the resulting MtUvrC variants were purified and characterized. Among them, residues Glu595 and Arg597 in the helix-hairpin-helix motif were found to be crucial for the interaction between MtUvrC and HJ; consequently, mutations in these residues, or inhibition of ATP hydrolysis, strongly abrogated its DNA-binding and endonuclease activities. Viewed together, these findings expand the substrate specificity landscape of UvrCs and provide crucial mechanistic insights into the interplay between NER and DNA replication/recombination.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India.
| | | | - Sagar S Barale
- Structural Bioinformatics Unit, Shivaji University, Kolhapur, India
| | - Kailas D Sonawane
- Department of Microbiology, Shivaji University, Kolhapur, India; Structural Bioinformatics Unit, Shivaji University, Kolhapur, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India.
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7
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Zhang X, Yin M, Hu J. Nucleotide excision repair: a versatile and smart toolkit. Acta Biochim Biophys Sin (Shanghai) 2022; 54:807-819. [PMID: 35975604 PMCID: PMC9828404 DOI: 10.3724/abbs.2022054] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Nucleotide excision repair (NER) is a major pathway to deal with bulky adducts induced by various environmental toxins in all cellular organisms. The two sub-pathways of NER, global genome repair (GGR) and transcription-coupled repair (TCR), differ in the damage recognition modes. In this review, we describe the molecular mechanism of NER in mammalian cells, especially the details of damage recognition steps in both sub-pathways. We also introduce new sequencing methods for genome-wide mapping of NER, as well as recent advances about NER in chromatin by these methods. Finally, the roles of NER factors in repairing oxidative damages and resolving R-loops are discussed.
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Affiliation(s)
| | | | - Jinchuan Hu
- Correspondence address. Tel: +86-21-54237702; E-mail:
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8
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Kapoor I, Shaw A, Naha A, Emam EAF, Varshney U. Role of the nucleotide excision repair pathway proteins (UvrB and UvrD2) in recycling UdgB, a base excision repair enzyme in Mycobacterium smegmatis. DNA Repair (Amst) 2022; 113:103316. [PMID: 35306347 DOI: 10.1016/j.dnarep.2022.103316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/30/2022] [Accepted: 03/02/2022] [Indexed: 11/24/2022]
Abstract
Cross-talks between DNA repair pathways are emerging as a crucial strategy in the maintenance of the genomic integrity. A double-stranded (ds) DNA specific DNA glycosylase, UdgB is known to excise uracil, hypoxanthine and ethenocytosine. We earlier showed that Mycobacterium smegmatis (Msm) UdgB stays back on the AP-sites it generates in the DNA upon excision of the damaged bases. Here, we show that in an Msm strain deleted for a nucleotide excision repair (NER) protein, UvrB (uvrB-), UdgB expression is toxic, and its deletion from the genome (udgB-) rescues the strain from the genotoxic stress. However, UdgB bound AP-site is not a direct substrate for NER in vitro. We show that UvrD2 and UvrB, known helicases with single-stranded (ss) DNA translocase activity, facilitate recycling of UdgB from AP-DNA. Our studies reveal that the helicases play an important role in exposing the AP-sites in DNA and make them available for further repair.
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Affiliation(s)
- Indu Kapoor
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Abhirup Shaw
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Arindam Naha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Elhassan Ali Fathi Emam
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Umesh Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.
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9
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Li W, Jones K, Burke TJ, Hossain MA, Lariscy L. Epigenetic Regulation of Nucleotide Excision Repair. Front Cell Dev Biol 2022; 10:847051. [PMID: 35465333 PMCID: PMC9023881 DOI: 10.3389/fcell.2022.847051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 03/24/2022] [Indexed: 12/30/2022] Open
Abstract
Genomic DNA is constantly attacked by a plethora of DNA damaging agents both from endogenous and exogenous sources. Nucleotide excision repair (NER) is the most versatile repair pathway that recognizes and removes a wide range of bulky and/or helix-distorting DNA lesions. Even though the molecular mechanism of NER is well studied through in vitro system, the NER process inside the cell is more complicated because the genomic DNA in eukaryotes is tightly packaged into chromosomes and compacted into a nucleus. Epigenetic modifications regulate gene activity and expression without changing the DNA sequence. The dynamics of epigenetic regulation play a crucial role during the in vivo NER process. In this review, we summarize recent advances in our understanding of the epigenetic regulation of NER.
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10
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van Toorn M, Turkyilmaz Y, Han S, Zhou D, Kim HS, Salas-Armenteros I, Kim M, Akita M, Wienholz F, Raams A, Ryu E, Kang S, Theil AF, Bezstarosti K, Tresini M, Giglia-Mari G, Demmers JA, Schärer OD, Choi JH, Vermeulen W, Marteijn JA. Active DNA damage eviction by HLTF stimulates nucleotide excision repair. Mol Cell 2022; 82:1343-1358.e8. [PMID: 35271816 PMCID: PMC9473497 DOI: 10.1016/j.molcel.2022.02.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/15/2021] [Accepted: 02/10/2022] [Indexed: 10/18/2022]
Abstract
Nucleotide excision repair (NER) counteracts the onset of cancer and aging by removing helix-distorting DNA lesions via a "cut-and-patch"-type reaction. The regulatory mechanisms that drive NER through its successive damage recognition, verification, incision, and gap restoration reaction steps remain elusive. Here, we show that the RAD5-related translocase HLTF facilitates repair through active eviction of incised damaged DNA together with associated repair proteins. Our data show a dual-incision-dependent recruitment of HLTF to the NER incision complex, which is mediated by HLTF's HIRAN domain that binds 3'-OH single-stranded DNA ends. HLTF's translocase motor subsequently promotes the dissociation of the stably damage-bound incision complex together with the incised oligonucleotide, allowing for an efficient PCNA loading and initiation of repair synthesis. Our findings uncover HLTF as an important NER factor that actively evicts DNA damage, thereby providing additional quality control by coordinating the transition between the excision and DNA synthesis steps to safeguard genome integrity.
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Affiliation(s)
- Marvin van Toorn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Yasemin Turkyilmaz
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Sueji Han
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea; Department of Bio-Analytical Science, University of Science & Technology, Daejeon 305-350, Republic of Korea
| | - Di Zhou
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Hyun-Suk Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Irene Salas-Armenteros
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Mihyun Kim
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea; Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Masaki Akita
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Franziska Wienholz
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Anja Raams
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Eunjin Ryu
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea; Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Sukhyun Kang
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea
| | - Arjan F Theil
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Karel Bezstarosti
- Proteomics Centre, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Maria Tresini
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Giuseppina Giglia-Mari
- Institut NeuroMyoGène (INMG), CNRS UMR 5310, INSERM U1217, Université de Lyon, Université Claude Bernard Lyon1, 16 rue Dubois, 69622 Villeurbanne Cedex, France
| | - Jeroen A Demmers
- Proteomics Centre, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Orlando D Schärer
- Center for Genomic Integrity, Institute for Basic Science, Ulsan 44919, Republic of Korea; Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Jun-Hyuk Choi
- Center for Bioanalysis, Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea; Department of Bio-Analytical Science, University of Science & Technology, Daejeon 305-350, Republic of Korea
| | - Wim Vermeulen
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands
| | - Jurgen A Marteijn
- Department of Molecular Genetics, Oncode Institute, Erasmus MC Cancer Institute, Erasmus University Medical Centre, Rotterdam, the Netherlands.
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11
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Courcelle J, Worley TK, Courcelle CT. Recombination Mediator Proteins: Misnomers That Are Key to Understanding the Genomic Instabilities in Cancer. Genes (Basel) 2022; 13:genes13030437. [PMID: 35327990 PMCID: PMC8950967 DOI: 10.3390/genes13030437] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/24/2022] [Accepted: 02/24/2022] [Indexed: 02/06/2023] Open
Abstract
Recombination mediator proteins have come into focus as promising targets for cancer therapy, with synthetic lethal approaches now clinically validated by the efficacy of PARP inhibitors in treating BRCA2 cancers and RECQ inhibitors in treating cancers with microsatellite instabilities. Thus, understanding the cellular role of recombination mediators is critically important, both to improve current therapies and develop new ones that target these pathways. Our mechanistic understanding of BRCA2 and RECQ began in Escherichia coli. Here, we review the cellular roles of RecF and RecQ, often considered functional homologs of these proteins in bacteria. Although these proteins were originally isolated as genes that were required during replication in sexual cell cycles that produce recombinant products, we now know that their function is similarly required during replication in asexual or mitotic-like cell cycles, where recombination is detrimental and generally not observed. Cells mutated in these gene products are unable to protect and process replication forks blocked at DNA damage, resulting in high rates of cell lethality and recombination events that compromise genome integrity during replication.
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12
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Kinetic and structural mechanism for DNA unwinding by a non-hexameric helicase. Nat Commun 2021; 12:7015. [PMID: 34853304 PMCID: PMC8636605 DOI: 10.1038/s41467-021-27304-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
UvrD, a model for non-hexameric Superfamily 1 helicases, utilizes ATP hydrolysis to translocate stepwise along single-stranded DNA and unwind the duplex. Previous estimates of its step size have been indirect, and a consensus on its stepping mechanism is lacking. To dissect the mechanism underlying DNA unwinding, we use optical tweezers to measure directly the stepping behavior of UvrD as it processes a DNA hairpin and show that UvrD exhibits a variable step size averaging ~3 base pairs. Analyzing stepping kinetics across ATP reveals the type and number of catalytic events that occur with different step sizes. These single-molecule data reveal a mechanism in which UvrD moves one base pair at a time but sequesters the nascent single strands, releasing them non-uniformly after a variable number of catalytic cycles. Molecular dynamics simulations point to a structural basis for this behavior, identifying the protein-DNA interactions responsible for strand sequestration. Based on structural and sequence alignment data, we propose that this stepping mechanism may be conserved among other non-hexameric helicases.
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13
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Urrutia-Irazabal I, Ault JR, Sobott F, Savery NJ, Dillingham MS. Analysis of the PcrA-RNA polymerase complex reveals a helicase interaction motif and a role for PcrA/UvrD helicase in the suppression of R-loops. eLife 2021; 10:68829. [PMID: 34279225 PMCID: PMC8318588 DOI: 10.7554/elife.68829] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/16/2021] [Indexed: 12/12/2022] Open
Abstract
The PcrA/UvrD helicase binds directly to RNA polymerase (RNAP) but the structural basis for this interaction and its functional significance have remained unclear. In this work, we used biochemical assays and hydrogen-deuterium exchange coupled to mass spectrometry to study the PcrA-RNAP complex. We find that PcrA binds tightly to a transcription elongation complex in a manner dependent on protein:protein interaction with the conserved PcrA C-terminal Tudor domain. The helicase binds predominantly to two positions on the surface of RNAP. The PcrA C-terminal domain engages a conserved region in a lineage-specific insert within the β subunit which we identify as a helicase interaction motif present in many other PcrA partner proteins, including the nucleotide excision repair factor UvrB. The catalytic core of the helicase binds near the RNA and DNA exit channels and blocking PcrA activity in vivo leads to the accumulation of R-loops. We propose a role for PcrA as an R-loop suppression factor that helps to minimize conflicts between transcription and other processes on DNA including replication.
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Affiliation(s)
- Inigo Urrutia-Irazabal
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - James R Ault
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Frank Sobott
- Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Nigel J Savery
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
| | - Mark S Dillingham
- DNA:Protein Interactions Unit, School of Biochemistry, University of Bristol. Biomedical Sciences Building, University Walk, Bristol, United Kingdom
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14
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Abstract
R-loops are nucleic acid hybrids which form when an RNA invades duplex DNA to pair with its template sequence. Although they are implicated in a growing number of gene regulatory processes, their mechanistic origins remain unclear. We here report real-time observations of cotranscriptional R-loop formation at single-molecule resolution and propose a mechanism for their formation. We show that the bacterial Mfd protein can simultaneously interact with both elongating RNA polymerase and upstream DNA, tethering the two together and partitioning the DNA into distinct supercoiled domains. A highly negatively supercoiled domain forms in between Mfd and RNA polymerase, and compensatory positive supercoiling appears in front of the RNA polymerase and behind Mfd. The nascent RNA invades the negatively supercoiled domain and forms a stable R-loop that can drive mutagenesis. This mechanism theoretically enables any protein that simultaneously binds an actively translocating RNA polymerase and upstream DNA to stimulate R-loop formation.
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15
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Selby CP, Lindsey-Boltz LA, Yang Y, Sancar A. Mycobacteria excise DNA damage in 12- or 13-nucleotide-long oligomers by prokaryotic-type dual incisions and performs transcription-coupled repair. J Biol Chem 2020; 295:17374-17380. [PMID: 33087442 PMCID: PMC7863889 DOI: 10.1074/jbc.ac120.016325] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 10/16/2020] [Indexed: 12/29/2022] Open
Abstract
In nucleotide excision repair, bulky DNA lesions such as UV-induced cyclobutane pyrimidine dimers are removed from the genome by concerted dual incisions bracketing the lesion, followed by gap filling and ligation. So far, two dual-incision patterns have been discovered: the prokaryotic type, which removes the damage in 11-13-nucleotide-long oligomers, and the eukaryotic type, which removes the damage in 24-32-nucleotide-long oligomers. However, a recent study reported that the UvrC protein of Mycobacterium tuberculosis removes damage in a manner analogous to yeast and humans in a 25-mer oligonucleotide arising from incisions at 15 nt from the 3´ end and 9 nt from the 5´ end flanking the damage. To test this model, we used the in vivo excision assay and the excision repair sequencing genome-wide repair mapping method developed in our laboratory to determine the repair pattern and genome-wide repair map of Mycobacterium smegmatis We find that M. smegmatis, which possesses homologs of the Escherichia coli uvrA, uvrB, and uvrC genes, removes cyclobutane pyrimidine dimers from the genome in a manner identical to the prokaryotic pattern by incising 7 nt 5´ and 3 or 4 nt 3´ to the photoproduct, and performs transcription-coupled repair in a manner similar to E. coli.
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Affiliation(s)
- Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Laura A Lindsey-Boltz
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Yanyan Yang
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
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16
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Thakur M, Agarwal A, Muniyappa K. The intrinsic ATPase activity of Mycobacterium tuberculosis UvrC is crucial for its damage-specific DNA incision function. FEBS J 2020; 288:1179-1200. [PMID: 32602194 DOI: 10.1111/febs.15465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/04/2020] [Accepted: 06/24/2020] [Indexed: 11/28/2022]
Abstract
To ensure genome stability, bacteria have evolved a network of DNA repair mechanisms; among them, the UvrABC-dependent nucleotide excision repair (NER) pathway is essential for the incision of a variety of bulky adducts generated by exogenous chemicals, UV radiation and by-products of cellular metabolism. However, very little is known about the enzymatic properties of Mycobacterium tuberculosis UvrABC excinuclease complex. Furthermore, the biochemical properties of Escherichia coli UvrC (EcUvrC) are not well understood (compared to UvrA and UvrB), perhaps due to its limited availability and/or activity instability in vitro. In addition, homology modelling of M. tuberculosis UvrC (MtUvrC) revealed the presence of a putative ATP-binding pocket, although its function remains unknown. To elucidate the biochemical properties of UvrC, we constructed and purified wild-type MtUvrC and its eight variants harbouring mutations within the ATP-binding pocket. The data from DNA-binding studies suggest that MtUvrC exhibits high-affinity for duplex DNA containing a bubble or fluorescein-dT moiety, over fluorescein-adducted single-stranded DNA. Most notably, MtUvrC has an intrinsic UvrB-independent ATPase activity, which drives dual incision of the damaged DNA strand. In contrast, EcUvrC is devoid of ATPase activity; however, it retains the ability to bind ATP at levels comparable to that of MtUvrC. The ATPase-deficient variants map to residues lining the MtUvrC ATP-binding pocket. Further analysis of these variants revealed separation of function between ATPase and DNA-binding activities in MtUvrC. Altogether, these findings reveal functional diversity of the bacterial NER machinery and a paradigm for the evolution of a catalytic scaffold in UvrC.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Ankit Agarwal
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bengaluru, India
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17
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Thakur M, Muniyappa K. Deciphering the essentiality and function of SxSx motif in Mycobacterium tuberculosis UvrB. Biochimie 2020; 170:94-105. [PMID: 31923481 DOI: 10.1016/j.biochi.2020.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/06/2020] [Indexed: 10/25/2022]
Abstract
The UvrB subunit is a central component of the UvrABC incision complex and plays a pivotal role in damage recognition, strand excision and repair synthesis. A conserved structural motif (the SxSx motif) present in UvrB is analogous to a similar motif (TxGx) in the helicases of superfamily 2, whose function is not fully understood. To elucidate the significance of the SxSx (Ser143-Val144-Ser145-Cys146) motif in Mycobacterium tuberculosis UvrB (MtUvrB), different variants of MtUvrB subunit were constructed and characterized. The SxSx motif indeed was found to be essential for MtUvrB function: while Ser143 and Cys146 residues within this motif were crucial for MtUvrB function, Ser145 plays an important but less essential role. The SxSx motif-deleted mutant was drastically attenuated and three single (S143A, S145A and C146A) mutants and a double (S143A/S145A) mutant exhibited various degrees of severity in their DNA-binding, DNA helicase and ATPase activities. Taken together, these results highlight a hitherto unrecognized role for SxSx motif in the catalytic activities of UvrB.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, 560012, India.
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18
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Thakur M, Badugu S, Muniyappa K. UvrA and UvrC subunits of the Mycobacterium tuberculosis UvrABC excinuclease interact independently of UvrB and DNA. FEBS Lett 2019; 594:851-863. [PMID: 31705809 DOI: 10.1002/1873-3468.13671] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 11/10/2022]
Abstract
The UvrABC excinuclease plays a vital role in bacterial nucleotide excision repair. While UvrA and UvrB subunits associate to form a UvrA2 B2 complex, interaction between UvrA and UvrC has not been demonstrated or quantified in any bacterial species. Here, using Mycobacterium tuberculosis UvrA (MtUvrA), UvrB (MtUvrB) and UvrC (MtUvrC) subunits, we show that MtUvrA binds to MtUvrB and equally well to MtUvrC with submicromolar affinity. Furthermore, MtUvrA forms a complex with MtUvrC both in vivo and in vitro, independently of DNA and UvrB. Collectively, these findings reveal new insights into the pairwise relationships between the subunits of the UvrABC incision complex.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Sugith Badugu
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Kalappa Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
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19
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Mohapatra S, Lin CT, Feng XA, Basu A, Ha T. Single-Molecule Analysis and Engineering of DNA Motors. Chem Rev 2019; 120:36-78. [DOI: 10.1021/acs.chemrev.9b00361] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
| | | | | | | | - Taekjip Ha
- Howard Hughes Medical Institute, Baltimore, Maryland 21205, United States
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20
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Abstract
The nucleotide excision repair (NER) system removes a variety of types of helix-distorting lesions from DNA through a dual incision mechanism, in which the damaged nucleotide bases are excised in the form of a small, excised, damage-containing single-stranded DNA oligonucleotide (sedDNA). Damage removal leaves a gap in the DNA template that must then be filled in by the action of a DNA polymerase and ligated to the downstream phosphodiester backbone in the DNA to complete the repair reaction. Defects in damage removal, sedDNA processing, or gap filling have the potential to be mutagenic and lethal to cells, and thus several human pathologies, including cancer and aging, are associated with defects in NER. This review summarizes our current understanding of NER with a focus on the enzymes that excise sedDNAs and restore the duplex DNA to its native state in human cells.
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Affiliation(s)
- Michael G Kemp
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH, United States.
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21
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Springall L, Hughes CD, Simons M, Azinas S, Van Houten B, Kad NM. Recruitment of UvrBC complexes to UV-induced damage in the absence of UvrA increases cell survival. Nucleic Acids Res 2019; 46:1256-1265. [PMID: 29240933 PMCID: PMC5814901 DOI: 10.1093/nar/gkx1244] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 12/01/2017] [Indexed: 02/05/2023] Open
Abstract
Nucleotide excision repair (NER) is the primary mechanism for removal of ultraviolet light (UV)-induced DNA photoproducts and is mechanistically conserved across all kingdoms of life. Bacterial NER involves damage recognition by UvrA2 and UvrB, followed by UvrC-mediated incision either side of the lesion. Here, using a combination of in vitro and in vivo single-molecule studies we show that a UvrBC complex is capable of lesion identification in the absence of UvrA. Single-molecule analysis of eGFP-labelled UvrB and UvrC in living cells showed that UV damage caused these proteins to switch from cytoplasmic diffusion to stable complexes on DNA. Surprisingly, ectopic expression of UvrC in a uvrA deleted strain increased UV survival. These data provide evidence for a previously unrealized mechanism of survival that can occur through direct lesion recognition by a UvrBC complex.
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Affiliation(s)
- Luke Springall
- School of Biological Sciences, University of Kent, Canterbury CT2 7NH, UK
| | - Craig D Hughes
- Department of Veterinary Medicine, University of Cambridge, Cambridge CB3 0ES, UK
| | - Michelle Simons
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK
| | - Stavros Azinas
- School of Biological Sciences, University of Essex, Colchester CO4 3SQ, UK
| | | | - Neil M Kad
- School of Biological Sciences, University of Kent, Canterbury CT2 7NH, UK
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22
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Cole JM, Acott JD, Courcelle CT, Courcelle J. Limited Capacity or Involvement of Excision Repair, Double-Strand Breaks, or Translesion Synthesis for Psoralen Cross-Link Repair in Escherichia coli. Genetics 2018; 210:99-112. [PMID: 30045856 PMCID: PMC6116958 DOI: 10.1534/genetics.118.301239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 07/18/2018] [Indexed: 02/06/2023] Open
Abstract
DNA interstrand cross-links are complex lesions that covalently bind complementary strands of DNA and whose mechanism of repair remains poorly understood. In Escherichia coli, several gene products have been proposed to be involved in cross-link repair based on the hypersensitivity of mutants to cross-linking agents. However, cross-linking agents induce several forms of DNA damage, making it challenging to attribute mutant hypersensitivity specifically to interstrand cross-links. To address this, we compared the survival of UVA-irradiated repair mutants in the presence of 8-methoxypsoralen-which forms interstrand cross-links and monoadducts-to that of angelicin-a congener forming only monoadducts. We show that incision by nucleotide excision repair is not required for resistance to interstrand cross-links. In addition, neither RecN nor DNA polymerases II, IV, or V is required for interstrand cross-link survival, arguing against models that involve critical roles for double-strand break repair or translesion synthesis in the repair process. Finally, estimates based on Southern analysis of DNA fragments in alkali agarose gels indicate that lethality occurs in wild-type cells at doses producing as few as one to two interstrand cross-links per genome. These observations suggest that E. coli may lack an efficient repair mechanism for this form of damage.
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Affiliation(s)
- Jessica M Cole
- Department of Biology, Portland State University, Oregon 97201
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23
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Catarina Teodoro Castro B, Cançado de Faria R, Faria BF, Azevedo V, Lara Dos Santos L, Júnior MC, Machado CR, de Oliveira Lopes D. UvrB protein of Corynebacterium pseudotuberculosis complements the phenotype of knockout Escherichia coli and recognizes DNA damage caused by UV radiation but not 8-oxoguanine in vitro. Gene 2018; 639:34-43. [PMID: 28974474 DOI: 10.1016/j.gene.2017.09.068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/17/2017] [Accepted: 09/29/2017] [Indexed: 11/27/2022]
Abstract
In prokaryotic cells, the UvrB protein plays a central role in nucleotide excision repair, which is involved in the recognition of bulky DNA lesions generated by chemical or physical agents. The present investigation aimed to characterize the uvrB gene of Corynebacterium pseudotuberculosis (CpuvrB) and evaluate its involvement in the DNA repair system of this pathogenic organism. In computational analysis, the alignment of the UvrB protein sequences of Escherichia coli, Mycobacterium tuberculosis, Bacillus caldotenax and Corynebacterium pseudotuberculosis showed high similarity and the catalytic amino acid residues and functional domains are preserved. A CpUvrB model was constructed by comparative modeling and presented structural similarity with the UvrB of E. coli. Moreover, in molecular docking analysis CpUvrB showed favorable interaction with EcUvrA and revealed a preserved ATP incorporation site. Heterologous functional complementation assays using E. coli uvrB-deficient cells exposed to UV irradiation showed that the CpUvrB protein contributed to an increased survival rate in relation to those in the absence of CpUvrB. Damaged oligonucleotides containing thymine dimer or 8-oxoguanine lesion were synthesized and incubated with CpUvrB protein, which was able to recognize and excise UV irradiation damage but not 8-oxoguanine. These results suggest that CpUvrB is involved in repairing lesions derived from UV light and encodes a protein orthologous to EcUvrB.
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Affiliation(s)
- Bárbara Catarina Teodoro Castro
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Rafael Cançado de Faria
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Bruna Franciele Faria
- Laboratory of Molecular Modeling, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Vasco Azevedo
- Laboratory of Cell and Molecular Genetics, Department of General Biology, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Luciana Lara Dos Santos
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Moacyr Comar Júnior
- Laboratory of Molecular Modeling, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
| | - Carlos Renato Machado
- Laboratory of Genetics and Biochemistry, Department of Biochemistry, ICB, Federal University of Minas Gerais, Av. Antônio Carlos, 6627, Belo Horizonte, MG 31270-901, Brazil.
| | - Débora de Oliveira Lopes
- Laboratory of Molecular Biology, Federal University of São João Del-Rei (CCO), Av. Sebastião Gonçalves Coelho, 400, Divinópolis, MG 35501-296, Brazil.
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24
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Chiou YY, Hu J, Sancar A, Selby CP. RNA polymerase II is released from the DNA template during transcription-coupled repair in mammalian cells. J Biol Chem 2017; 293:2476-2486. [PMID: 29282293 DOI: 10.1074/jbc.ra117.000971] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/19/2017] [Indexed: 11/06/2022] Open
Abstract
In mammalian cells, bulky DNA adducts located in the template but not the coding strand of genes block elongation by RNA polymerase II (RNAPII). The blocked RNAPII targets these transcription-blocking adducts to undergo more rapid excision repair than adducts located elsewhere in the genome. In excision repair, coupled incisions are made in the damaged DNA strand on both sides of the adduct. The fate of RNAPII in the course of this transcription-coupled repair (TCR) pathway is unclear. To address the fate of RNAPII, we used methods that control transcription to initiate a discrete "wave" of elongation complexes. Analyzing genome-wide transcription and repair by next-generation sequencing, we identified locations of elongation complexes and transcription-repair coupling events in genes throughout the genome. Using UV-exposed human skin fibroblasts, we found that, at the dose used, a single wave of elongation complexes was blocked within the first 25 kb of genes. TCR occurred where the elongation complexes were blocked, and repair was associated with the dissociation of these complexes. These results indicate that individual elongation complexes do not engage in multiple rounds of TCR with successive lesions. Our results are consistent with a model in which RNAPII is dissociated after the dual incision of the transcription-blocking lesion, perhaps by Cockayne syndrome group B translocase, or during the synthesis of a repair patch.
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Affiliation(s)
- Yi-Ying Chiou
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and.,the Institute of Biochemistry, National Chung Hsing University, Taichung 402, Taiwan
| | - Jinchuan Hu
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
| | - Aziz Sancar
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
| | - Christopher P Selby
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
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25
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Escherichia coli and Neisseria gonorrhoeae UvrD helicase unwinds G4 DNA structures. Biochem J 2017; 474:3579-3597. [PMID: 28916651 DOI: 10.1042/bcj20170587] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 11/17/2022]
Abstract
G-quadruplex (G4) secondary structures have been implicated in various biological processes, including gene expression, DNA replication and telomere maintenance. However, unresolved G4 structures impede replication progression which can lead to the generation of DNA double-strand breaks and genome instability. Helicases have been shown to resolve G4 structures to facilitate faithful duplication of the genome. Escherichia coli UvrD (EcUvrD) helicase plays a crucial role in nucleotide excision repair, mismatch repair and in the regulation of homologous recombination. Here, we demonstrate a novel role of E. coli and Neisseria gonorrhoeae UvrD in resolving G4 tetraplexes. EcUvrD and Ngonorrhoeae UvrD were proficient in unwinding previously characterized tetramolecular G4 structures. Notably, EcUvrD was equally efficient in resolving tetramolecular and bimolecular G4 DNA that were derived from the potential G4-forming sequences from the genome of E. coli Interestingly, in addition to resolving intermolecular G4 structures, EcUvrD was robust in unwinding intramolecular G4 structures. These data for the first time provide evidence for the role of UvrD in the resolution of G4 structures, which has implications for the in vivo role of UvrD helicase in G4 DNA resolution and genome maintenance.
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26
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Adebali O, Sancar A, Selby CP. Mfd translocase is necessary and sufficient for transcription-coupled repair in Escherichia coli. J Biol Chem 2017; 292:18386-18391. [PMID: 28986449 DOI: 10.1074/jbc.c117.818807] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/04/2017] [Indexed: 12/26/2022] Open
Abstract
Nucleotide excision repair in Escherichia coli is stimulated by transcription, specifically in the transcribed strand. Previously, it was shown that this transcription-coupled repair (TCR) is mediated by the Mfd translocase. Recently, it was proposed that in fact the majority of TCR in E. coli is catalyzed by a second pathway ("backtracking-mediated TCR") that is dependent on the UvrD helicase and the guanosine pentaphosphate (ppGpp) alarmone/stringent response regulator. Recently, we reported that as measured by the excision repair-sequencing (XR-seq), UvrD plays no role in TCR genome-wide. Here, we tested the role of ppGpp and UvrD in TCR genome-wide and in the lacZ operon using the XR-seq method, which directly measures repair. We found that the mfd mutation abolishes TCR genome-wide and in the lacZ operon. In contrast, the relA-spoT- mutant deficient in ppGpp synthesis carries out normal TCR. We conclude that UvrD and ppGpp play no role in TCR in E. coli.
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Affiliation(s)
- Ogun Adebali
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
| | - Aziz Sancar
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
| | - Christopher P Selby
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260
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27
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Hu J, Selby CP, Adar S, Adebali O, Sancar A. Molecular mechanisms and genomic maps of DNA excision repair in Escherichia coli and humans. J Biol Chem 2017; 292:15588-15597. [PMID: 28798238 DOI: 10.1074/jbc.r117.807453] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Nucleotide excision repair is a major DNA repair mechanism in all cellular organisms. In this repair system, the DNA damage is removed by concerted dual incisions bracketing the damage and at a precise distance from the damage. Here, we review the basic mechanisms of excision repair in Escherichia coli and humans and the recent genome-wide mapping of DNA damage and repair in these organisms at single-nucleotide resolution.
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Affiliation(s)
- Jinchuan Hu
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
| | - Christopher P Selby
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
| | - Sheera Adar
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and.,the Department of Microbiology and Molecular Genetics, Hebrew University-Hadassah Medical School, Ein Kerem 71120, Jerusalem, Israel
| | - Ogun Adebali
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
| | - Aziz Sancar
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599-7260 and
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28
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Genomic sequencing of a strain of Acinetobacter baumannii and potential mechanisms to antibiotics resistance. INFECTION GENETICS AND EVOLUTION 2017; 50:20-24. [DOI: 10.1016/j.meegid.2017.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 01/02/2017] [Accepted: 02/01/2017] [Indexed: 12/26/2022]
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29
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Genome-wide transcription-coupled repair in Escherichia coli is mediated by the Mfd translocase. Proc Natl Acad Sci U S A 2017; 114:E2116-E2125. [PMID: 28167766 PMCID: PMC5358382 DOI: 10.1073/pnas.1700230114] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
In transcription-coupled repair (TCR), nucleotide excision repair occurs most rapidly in the template strand of actively transcribed genes. TCR has been observed in a limited set of genes directly assayed in Escherichia coli cells. In vitro, Mfd translocase performs reactions necessary to mediate TCR: It removes RNA polymerase blocked by a template strand lesion and rapidly delivers repair enzymes to the lesion. This study applied excision repair sequencing methodology to map the location of repair sites in different E. coli strains. Results showed that Mfd-dependent TCR is widespread in the E. coli genome. Results with UvrD helicase demonstrated its role in basal repair, but no overall role in TCR. We used high-throughput sequencing of short, cyclobutane pyrimidine dimer-containing ssDNA oligos generated during repair of UV-induced damage to study that process at both mechanistic and systemic levels in Escherichia coli. Numerous important insights on DNA repair were obtained, bringing clarity to the respective roles of UvrD helicase and Mfd translocase in repair of UV-induced damage. Mechanistically, experiments showed that the predominant role of UvrD in vivo is to unwind the excised 13-mer from dsDNA and that mutation of uvrD results in remarkable protection of that oligo from exonuclease activity as it remains hybridized to the dsDNA. Genome-wide analysis of the transcribed strand/nontranscribed strand (TS/NTS) repair ratio demonstrated that deletion of mfd globally shifts the distribution of TS/NTS ratios downward by a factor of about 2 on average for the most highly transcribed genes. Even for the least transcribed genes, Mfd played a role in preferential repair of the transcribed strand. On the other hand, mutation of uvrD, if anything, slightly pushed the distribution of TS/NTS ratios to higher ratios. These results indicate that Mfd is the transcription repair-coupling factor whereas UvrD plays a role in excision repair by aiding the catalytic turnover of excision repair proteins.
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30
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Luo J, Kong M, Liu L, Samanta S, Van Houten B, Deiters A. Optical Control of DNA Helicase Function through Genetic Code Expansion. Chembiochem 2017; 18:466-469. [PMID: 28120472 DOI: 10.1002/cbic.201600624] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Indexed: 12/14/2022]
Abstract
Nucleotide excision repair (NER) is a general DNA repair mechanism that is capable of removing a wide variety of DNA lesions induced by physical or chemical insults. UvrD, a member of the helicase SF1 superfamily, plays an essential role in bacterial NER by unwinding the duplex DNA in the 3' to 5' direction to displace the lesion-containing strand. In order to achieve conditional control over NER, we generated a light-activated DNA helicase. This was achieved through a site-specific incorporation of a genetically encoded hydroxycoumarin lysine at a crucial position in the ATP-binding pocket of UvrD. The resulting caged enzyme was completely inactive in several functional assays. Moreover, enzymatic activity of the optically triggered UvrD was comparable to that of the wild-type protein, thus demonstrating excellent OFF to ON switching of the helicase. The developed approach provides optical control of NER, thereby laying a foundation for the regulation of ATP-dependent helicase functions in higher organisms. In addition, this methodology is applicable to the light-activation of a wide range of ATPases.
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Affiliation(s)
- Ji Luo
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Muwen Kong
- Department of Pharmacology and Chemical Biology, USA.,The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, 15213, USA
| | - Lili Liu
- The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, 15213, USA
| | - Subhas Samanta
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA
| | - Bennett Van Houten
- Department of Pharmacology and Chemical Biology, USA.,The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, 15213, USA
| | - Alexander Deiters
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, 15260, USA.,The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania, 15213, USA
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31
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Selby CP. Mfd Protein and Transcription-Repair Coupling in Escherichia coli. Photochem Photobiol 2017; 93:280-295. [PMID: 27864884 DOI: 10.1111/php.12675] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/18/2016] [Indexed: 01/30/2023]
Abstract
In 1989, transcription-repair coupling (TRC) was first described in Escherichia coli, as the transcription-dependent, preferential nucleotide excision repair (NER) of UV photoproducts located in the template DNA strand. This finding led to pioneering biochemical studies of TRC in the laboratory of Professor Aziz Sancar, where, at the time, major contributions were being made toward understanding the roles of the UvrA, UvrB and UvrC proteins in NER. When the repair studies were extended to TRC, template but not coding strand lesions were found to block RNA polymerase (RNAP) in vitro, and unexpectedly, the blocked RNAP inhibited NER. A transcription-repair coupling factor, also called Mfd protein, was found to remove the blocked RNAP, deliver the repair enzyme to the lesion and thereby mediate more rapid repair of the transcription-blocking lesion compared with lesions elsewhere. Structural and functional analyses of Mfd protein revealed helicase motifs responsible for ATP hydrolysis and DNA binding, and regions that interact with RNAP and UvrA. These and additional studies provided a basis upon which other investigators, in following decades, have characterized fascinating and unexpected structural and mechanistic features of Mfd, revealed the possible existence of additional pathways of TRC and discovered additional roles of Mfd in the cell.
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Affiliation(s)
- Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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Kemp MG, Hu J. PostExcision Events in Human Nucleotide Excision Repair. Photochem Photobiol 2016; 93:178-191. [PMID: 27645806 DOI: 10.1111/php.12641] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/26/2016] [Indexed: 12/27/2022]
Abstract
The nucleotide excision repair system removes a wide variety of DNA lesions from the human genome, including photoproducts induced by ultraviolet (UV) wavelengths of sunlight. A defining feature of nucleotide excision repair is its dual incision mechanism, in which two nucleolytic incision events on the damaged strand of DNA at sites bracketing the lesion generate a damage-containing DNA oligonucleotide and a single-stranded DNA gap approximately 30 nucleotides in length. Although the early events of nucleotide excision repair, which include lesion recognition and the dual incisions, have been explored in detail and are reasonably well understood, the fate of the single-stranded DNA gaps and excised oligonucleotide products of repair have not been as extensively examined. In this review, recent findings that address these less-explored aspects of nucleotide excision repair are discussed and support the concept that postincision gap and excised oligonucleotide processing are critical steps in the cellular response to DNA damage induced by UV light and other environmental carcinogens. Defects in these latter stages of repair lead to cell death and other DNA damage signaling responses and may therefore contribute to a number of human disease states associated with exposure to UV wavelengths of sunlight, including skin cancer, aging and autoimmunity.
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Affiliation(s)
- Michael G Kemp
- Department of Pharmacology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH
| | - Jinchuan Hu
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC
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Cho Endonuclease Functions during DNA Interstrand Cross-Link Repair in Escherichia coli. J Bacteriol 2016; 198:3099-3108. [PMID: 27573016 DOI: 10.1128/jb.00509-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/22/2016] [Indexed: 01/21/2023] Open
Abstract
DNA interstrand cross-links are complex lesions that covalently link both strands of the duplex DNA. Lesion removal is proposed to be initiated via the UvrABC nucleotide excision repair complex; however, less is known about the subsequent steps of this complex repair pathway. In this study, we characterized the contribution of nucleotide excision repair mutants to survival in the presence of psoralen-induced damage. Unexpectedly, we observed that the nucleotide excision repair mutants exhibit differential sensitivity to psoralen-induced damage, with uvrC mutants being less sensitive than either uvrA or uvrB We show that Cho, an alternative endonuclease, acts with UvrAB and is responsible for the reduced hypersensitivity of uvrC mutants. We find that Cho's contribution to survival correlates with the presence of DNA interstrand cross-links, rather than monoadducts, and operates at a step after, or independently from, the initial incision during the global repair of psoralen DNA adducts from the genome. IMPORTANCE DNA interstrand cross-links are complex lesions that covalently bind to both strands of the duplex DNA and whose mechanism of repair remains poorly understood. In this study, we show that Cho, an alternative endonuclease, acts with UvrAB and participates in the repair of DNA interstrand cross-links formed in the presence of photoactivated psoralens. Cho's contribution to survival correlates with the presence of DNA interstrand cross-links and operates at a step after, or independently from, the initial incision during the repair process.
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Thakur M, Kumar MBJ, Muniyappa K. Mycobacterium tuberculosis UvrB Is a Robust DNA-Stimulated ATPase That Also Possesses Structure-Specific ATP-Dependent DNA Helicase Activity. Biochemistry 2016; 55:5865-5883. [PMID: 27618337 DOI: 10.1021/acs.biochem.6b00558] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Much is known about the Escherichia coli nucleotide excision repair (NER) pathway; however, very little is understood about the proteins involved and the molecular mechanism of NER in mycobacteria. In this study, we show that Mycobacterium tuberculosis UvrB (MtUvrB), which exists in solution as a monomer, binds to DNA in a structure-dependent manner. A systematic examination of MtUvrB substrate specificity reveals that it associates preferentially with single-stranded DNA, duplexes with 3' or 5' overhangs, and linear duplex DNA with splayed arms. Whereas E. coli UvrB (EcUvrB) binds weakly to undamaged DNA and has no ATPase activity, MtUvrB possesses intrinsic ATPase activity that is greatly stimulated by both single- and double-stranded DNA. Strikingly, we found that MtUvrB, but not EcUvrB, possesses the DNA unwinding activity characteristic of an ATP-dependent DNA helicase. The helicase activity of MtUvrB proceeds in the 3' to 5' direction and is strongly modulated by a nontranslocating 5' single-stranded tail, indicating that in addition to the translocating strand it also interacts with the 5' end of the substrate. The fraction of DNA unwound by MtUvrB decreases significantly as the length of the duplex increases: it fails to unwind duplexes longer than 70 bp. These results, on one hand, reveal significant mechanistic differences between MtUvrB and EcUvrB and, on the other, support an alternative role for UvrB in the processing of key DNA replication intermediates. Altogether, our findings provide insights into the catalytic functions of UvrB and lay the foundation for further understanding of the NER pathway in M. tuberculosis.
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Affiliation(s)
- Manoj Thakur
- Department of Biochemistry, Indian Institute of Science , Bangalore 560012, India
| | - Mohan B J Kumar
- Department of Biochemistry, Indian Institute of Science , Bangalore 560012, India
| | - K Muniyappa
- Department of Biochemistry, Indian Institute of Science , Bangalore 560012, India
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The excluded DNA strand is SEW important for hexameric helicase unwinding. Methods 2016; 108:79-91. [DOI: 10.1016/j.ymeth.2016.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 02/04/2023] Open
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Sancar A. Mechanisms of DNA Repair by Photolyase and Excision Nuclease (Nobel Lecture). Angew Chem Int Ed Engl 2016; 55:8502-27. [PMID: 27337655 DOI: 10.1002/anie.201601524] [Citation(s) in RCA: 177] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Indexed: 01/27/2023]
Abstract
Ultraviolet light damages DNA by converting two adjacent thymines into a thymine dimer which is potentially mutagenic, carcinogenic, or lethal to the organism. This damage is repaired by photolyase and the nucleotide excision repair system in E. coli by nucleotide excision repair in humans. The work leading to these results is presented by Aziz Sancar in his Nobel Lecture.
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Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA.
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Sancar A. Mechanismen der DNA-Reparatur durch Photolyasen und Exzisionsnukleasen (Nobel-Aufsatz). Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201601524] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Aziz Sancar
- Department of Biochemistry and Biophysics; University of North Carolina School of Medicine; Chapel Hill North Carolina USA
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Bavi R, Kumar R, Rampogu S, Son M, Park C, Baek A, Kim HH, Suh JK, Park SJ, Lee KW. Molecular interactions of UvrB protein and DNA from Helicobacter pylori: Insight into a molecular modeling approach. Comput Biol Med 2016; 75:181-9. [PMID: 27315565 DOI: 10.1016/j.compbiomed.2016.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Revised: 06/02/2016] [Accepted: 06/03/2016] [Indexed: 12/11/2022]
Abstract
Helicobacter pylori (H. pylori) persevere in the human stomach, an environment in which they encounter many DNA-damaging conditions, including gastric acidity. The pathogenicity of H. pylori is enhanced by its well-developed DNA repair mechanism, thought of as 'machinery,' such as nucleotide excision repair (NER). NER involves multi-enzymatic excinuclease proteins (UvrABC endonuclease), which repair damaged DNA in a sequential manner. UvrB is the central component in prokaryotic NER, essential for damage recognition. Therefore, molecular modeling studies of UvrB protein from H. pylori are carried out with homology modeling and molecular dynamics (MD) simulations. The results reveal that the predicted structure is bound to a DNA hairpin with 3-bp stem, an 11-nucleotide loop, and 3-nt 3' overhang. In addition, a mutation of the Y96A variant indicates reduction in the binding affinity for DNA. Free-energy calculations demonstrate the stability of the complex and help identify key residues in various interactions based on residue decomposition analysis. Stability comparative studies between wild type and mutant protein-DNA complexes indicate that the former is relatively more stable than the mutant form. This predicted model could also be useful in designing new inhibitors for UvrB protein, as well as preventing the pathogenesis of H. pylori.
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Affiliation(s)
- Rohit Bavi
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Raj Kumar
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Shailima Rampogu
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Minky Son
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Chanin Park
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Ayoung Baek
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea
| | - Hyong-Ha Kim
- Division of Quality of Life, Korea Research Institute of Standards and Science, Daejeon 305-340, Republic of Korea
| | - Jung-Keun Suh
- Bio Computing Major, Korean German Institute of Technology, Seoul 157-033, Republic of Korea
| | - Seok Ju Park
- Department of Internal Medicine, College of Medicine, Busan Paik Hospital, Inje University, Republic of Korea.
| | - Keun Woo Lee
- Division of Applied Life Science (BK21 Plus), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), 501 Jinju-daero, Jinju 52828, Republic of Korea.
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Van Houten B. A tale of two cities: A tribute to Aziz Sancar's Nobel Prize in Chemistry for his molecular characterization of NER. DNA Repair (Amst) 2016; 37:A3-A13. [PMID: 26861185 PMCID: PMC5068483 DOI: 10.1016/j.dnarep.2015.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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40
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Orren DK. The Nobel Prize in Chemistry 2015: Exciting discoveries in DNA repair by Aziz Sancar. SCIENCE CHINA-LIFE SCIENCES 2015; 59:97-102. [PMID: 26712032 DOI: 10.1007/s11427-015-4994-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/16/2015] [Indexed: 11/27/2022]
Affiliation(s)
- David K Orren
- Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine and Markey Cancer Center, University of Kentucky, Lexington, KY, 40536-0305, USA.
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41
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Comstock MJ, Whitley KD, Jia H, Sokoloski J, Lohman TM, Ha T, Chemla YR. Protein structure. Direct observation of structure-function relationship in a nucleic acid-processing enzyme. Science 2015; 348:352-4. [PMID: 25883359 DOI: 10.1126/science.aaa0130] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/24/2015] [Indexed: 12/24/2022]
Abstract
The relationship between protein three-dimensional structure and function is essential for mechanism determination. Unfortunately, most techniques do not provide a direct measurement of this relationship. Structural data are typically limited to static pictures, and function must be inferred. Conversely, functional assays usually provide little information on structural conformation. We developed a single-molecule technique combining optical tweezers and fluorescence microscopy that allows for both measurements simultaneously. Here we present measurements of UvrD, a DNA repair helicase, that directly and unambiguously reveal the connection between its structure and function. Our data reveal that UvrD exhibits two distinct types of unwinding activity regulated by its stoichiometry. Furthermore, two UvrD conformational states, termed "closed" and "open," correlate with movement toward or away from the DNA fork.
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Affiliation(s)
- Matthew J Comstock
- Department of Physics, Center for the Physics of Living Cells, and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kevin D Whitley
- Department of Physics, Center for the Physics of Living Cells, and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Haifeng Jia
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Joshua Sokoloski
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Timothy M Lohman
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Taekjip Ha
- Department of Physics, Center for the Physics of Living Cells, and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Howard Hughes Medical Institute, Urbana, IL 61801, USA. Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yann R Chemla
- Department of Physics, Center for the Physics of Living Cells, and Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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42
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Accessory Replicative Helicases and the Replication of Protein-Bound DNA. J Mol Biol 2014; 426:3917-3928. [DOI: 10.1016/j.jmb.2014.10.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 09/29/2014] [Accepted: 10/06/2014] [Indexed: 12/29/2022]
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43
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Epshtein V. UvrD helicase: an old dog with a new trick: how one step backward leads to many steps forward. Bioessays 2014; 37:12-9. [PMID: 25345862 DOI: 10.1002/bies.201400106] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Transcription-coupled repair (TCR) is a phenomenon that exists in a wide variety of organisms from bacteria to humans. This mechanism allows cells to repair the actively transcribed DNA strand much faster than the non-transcribed one. At the sites of bulky DNA damage RNA polymerase stalls, initiating recruitment of the repair machinery. It is a commonly accepted paradigm that bacterial cells utilize a sole coupling factor, called Mfd to initiate TCR. According to that model, Mfd removes transcription complexes stalled at the lesion site and simultaneously recruits repair machinery. However, this model was recently put in doubt by various discrepancies between the proposed universal role of Mfd in the TCR and its biochemical and phenotypical properties. Here, I present a second pathway of bacterial TCR recently discovered in my laboratory, which does not involve Mfd but implicates a common repair factor, UvrD, in a central position in the process.
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Affiliation(s)
- Vitaliy Epshtein
- Department of Biochemistry, New York University, Langhorn Medical Center, New York, NY, USA
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44
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Meiners MJ, Tahmaseb K, Matson SW. The UvrD303 hyper-helicase exhibits increased processivity. J Biol Chem 2014; 289:17100-10. [PMID: 24798324 DOI: 10.1074/jbc.m114.565309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
DNA helicases use energy derived from nucleoside 5'-triphosphate hydrolysis to catalyze the separation of double-stranded DNA into single-stranded intermediates for replication, recombination, and repair. Escherichia coli helicase II (UvrD) functions in methyl-directed mismatch repair, nucleotide excision repair, and homologous recombination. A previously discovered 2-amino acid substitution of residues 403 and 404 (both Asp → Ala) in the 2B subdomain of UvrD (uvrD303) confers an antimutator and UV-sensitive phenotype on cells expressing this allele. The purified protein exhibits a "hyper-helicase" unwinding activity in vitro. Using rapid quench, pre-steady state kinetic experiments we show the increased helicase activity of UvrD303 is due to an increase in the processivity of the unwinding reaction. We suggest that this mutation in the 2B subdomain results in a weakened interaction with the 1B subdomain, allowing the helicase to adopt a more open conformation. This is consistent with the idea that the 2B subdomain may have an autoregulatory role. The UvrD303 mutation may enable the helicase to unwind DNA via a "strand displacement" mechanism, which is similar to the mechanism used to processively translocate along single-stranded DNA, and the increased unwinding processivity may contribute directly to the antimutator phenotype.
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Affiliation(s)
| | | | - Steven W Matson
- From the Department of Biology, Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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45
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Van Houten B, Kad N. Investigation of bacterial nucleotide excision repair using single-molecule techniques. DNA Repair (Amst) 2014; 20:41-48. [PMID: 24472181 PMCID: PMC5053424 DOI: 10.1016/j.dnarep.2013.10.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 12/23/2022]
Abstract
Despite three decades of biochemical and structural analysis of the prokaryotic nucleotide excision repair (NER) system, many intriguing questions remain with regard to how the UvrA, UvrB, and UvrC proteins detect, verify and remove a wide range of DNA lesions. Single-molecule techniques have begun to allow more detailed understanding of the kinetics and action mechanism of this complex process. This article reviews how atomic force microscopy and fluorescence microscopy have captured new glimpses of how these proteins work together to mediate NER.
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Affiliation(s)
- Bennett Van Houten
- Department of Pharmacology and Chemical Biology, University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Neil Kad
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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46
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Lee KS, Balci H, Jia H, Lohman TM, Ha T. Direct imaging of single UvrD helicase dynamics on long single-stranded DNA. Nat Commun 2013; 4:1878. [PMID: 23695672 PMCID: PMC3674262 DOI: 10.1038/ncomms2882] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 04/12/2013] [Indexed: 12/31/2022] Open
Abstract
Fluorescence imaging of single-protein dynamics on DNA has been largely limited to double-stranded DNA or short single-stranded DNA. We have developed a hybrid approach for observing single proteins moving on laterally stretched kilobase-sized ssDNA. Here we probed the single-stranded DNA translocase activity of Escherichia coli UvrD by single fluorophore tracking, while monitoring DNA unwinding activity with optical tweezers to capture the entire sequence of protein binding, single-stranded DNA translocation and multiple pathways of unwinding initiation. The results directly demonstrate that the UvrD monomer is a highly processive single-stranded DNA translocase that is stopped by a double-stranded DNA, whereas two monomers are required to unwind DNA to a detectable degree. The single-stranded DNA translocation rate does not depend on the force applied and displays a remarkable homogeneity, whereas the unwinding rate shows significant heterogeneity. These findings demonstrate that UvrD assembly state regulates its DNA helicase activity with functional implications for its stepping mechanism, and also reveal a previously unappreciated complexity in the active species during unwinding. Tracking single molecules on long stretches of single-stranded DNA poses technical challenges due to its propensity to form hairpin structures. To solve this problem, the authors combine TIRF microscopy with optical tweezers to stretch the DNA and capture the dynamics of DNA unwinding by UvrD DNA helicase.
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Affiliation(s)
- Kyung Suk Lee
- Department of Physics, Center for Physics in Living Cells and Institute for Genomic Biology, University of Illinois, Urbana-Champaign, Urbana, Illinois 61801-2902, USA
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47
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Tolerance of Escherichia coli to fluoroquinolone antibiotics depends on specific components of the SOS response pathway. Genetics 2013; 195:1265-76. [PMID: 24077306 DOI: 10.1534/genetics.113.152306] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Bacteria exposed to bactericidal fluoroquinolone (FQ) antibiotics can survive without becoming genetically resistant. Survival of these phenotypically resistant cells, commonly called "persisters," depends on the SOS gene network. We have examined mutants in all known SOS-regulated genes to identify functions essential for tolerance in Escherichia coli. The absence of DinG and UvrD helicases and the Holliday junction processing enzymes RuvA and RuvB leads to a decrease in survival. Analysis of the respective mutants indicates that, in addition to repair of double-strand breaks, tolerance depends on the repair of collapsed replication forks and stalled transcription complexes. Mutation in recF results in increased survival, which identifies RecAF recombination as a poisoning mechanism not previously linked to FQ lethality. DinG acts upstream of SOS promoting its induction, whereas RuvAB participates in repair only. UvrD directly promotes all repair processes initiated by FQ-induced damage and prevents RecAF-dependent misrepair, making it one of the crucial SOS functions required for tolerance.
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48
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Parulekar RS, Barage SH, Jalkute CB, Dhanavade MJ, Fandilolu PM, Sonawane KD. Homology Modeling, Molecular Docking and DNA Binding Studies of Nucleotide Excision Repair UvrC Protein from M. tuberculosis. Protein J 2013; 32:467-76. [DOI: 10.1007/s10930-013-9506-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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49
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Hughes CD, Wang H, Ghodke H, Simons M, Towheed A, Peng Y, Van Houten B, Kad NM. Real-time single-molecule imaging reveals a direct interaction between UvrC and UvrB on DNA tightropes. Nucleic Acids Res 2013; 41:4901-12. [PMID: 23511970 PMCID: PMC3643590 DOI: 10.1093/nar/gkt177] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Nucleotide excision DNA repair is mechanistically conserved across all kingdoms of life. In prokaryotes, this multi-enzyme process requires six proteins: UvrA–D, DNA polymerase I and DNA ligase. To examine how UvrC locates the UvrB–DNA pre-incision complex at a site of damage, we have labeled UvrB and UvrC with different colored quantum dots and quantitatively observed their interactions with DNA tightropes under a variety of solution conditions using oblique angle fluorescence imaging. Alone, UvrC predominantly interacts statically with DNA at low salt. Surprisingly, however, UvrC and UvrB together in solution bind to form the previously unseen UvrBC complex on duplex DNA. This UvrBC complex is highly motile and engages in unbiased one-dimensional diffusion. To test whether UvrB makes direct contact with the DNA in the UvrBC–DNA complex, we investigated three UvrB mutants: Y96A, a β-hairpin deletion and D338N. These mutants affected the motile properties of the UvrBC complex, indicating that UvrB is in intimate contact with the DNA when bound to UvrC. Given the in vivo excess of UvrB and the abundance of UvrBC in our experiments, this newly identified complex is likely to be the predominant form of UvrC in the cell.
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Affiliation(s)
- Craig D Hughes
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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50
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Abstract
Nucleotide excision repair (NER) has allowed bacteria to flourish in many different niches around the globe that inflict harsh environmental damage to their genetic material. NER is remarkable because of its diverse substrate repertoire, which differs greatly in chemical composition and structure. Recent advances in structural biology and single-molecule studies have given great insight into the structure and function of NER components. This ensemble of proteins orchestrates faithful removal of toxic DNA lesions through a multistep process. The damaged nucleotide is recognized by dynamic probing of the DNA structure that is then verified and marked for dual incisions followed by excision of the damage and surrounding nucleotides. The opposite DNA strand serves as a template for repair, which is completed after resynthesis and ligation.
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Affiliation(s)
- Caroline Kisker
- Rudolf-Virchow-Center for Experimental Biomedicine, University of Wuerzburg, 97080 Wuerzburg, Germany.
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