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Pal S, Yuvaraj R, Krishnan H, Venkatraman B, Abraham J, Gopinathan A. Unraveling radiation resistance strategies in two bacterial strains from the high background radiation area of Chavara-Neendakara: A comprehensive whole genome analysis. PLoS One 2024; 19:e0304810. [PMID: 38857267 PMCID: PMC11164402 DOI: 10.1371/journal.pone.0304810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Accepted: 05/18/2024] [Indexed: 06/12/2024] Open
Abstract
This paper reports the results of gamma irradiation experiments and whole genome sequencing (WGS) performed on vegetative cells of two radiation resistant bacterial strains, Metabacillus halosaccharovorans (VITHBRA001) and Bacillus paralicheniformis (VITHBRA024) (D10 values 2.32 kGy and 1.42 kGy, respectively), inhabiting the top-ranking high background radiation area (HBRA) of Chavara-Neendakara placer deposit (Kerala, India). The present investigation has been carried out in the context that information on strategies of bacteria having mid-range resistance for gamma radiation is inadequate. WGS, annotation, COG and KEGG analyses and manual curation of genes helped us address the possible pathways involved in the major domains of radiation resistance, involving recombination repair, base excision repair, nucleotide excision repair and mismatch repair, and the antioxidant genes, which the candidate could activate to survive under ionizing radiation. Additionally, with the help of these data, we could compare the candidate strains with that of the extremely radiation resistant model bacterium Deinococccus radiodurans, so as to find the commonalities existing in their strategies of resistance on the one hand, and also the rationale behind the difference in D10, on the other. Genomic analysis of VITHBRA001 and VITHBRA024 has further helped us ascertain the difference in capability of radiation resistance between the two strains. Significantly, the genes such as uvsE (NER), frnE (protein protection), ppk1 and ppx (non-enzymatic metabolite production) and those for carotenoid biosynthesis, are endogenous to VITHBRA001, but absent in VITHBRA024, which could explain the former's better radiation resistance. Further, this is the first-time study performed on any bacterial population inhabiting an HBRA. This study also brings forward the two species whose radiation resistance has not been reported thus far, and add to the knowledge on radiation resistant capabilities of the phylum Firmicutes which are abundantly observed in extreme environment.
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Affiliation(s)
- Sowptika Pal
- Molecular Endocrinology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Ramani Yuvaraj
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Hari Krishnan
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Balasubramanian Venkatraman
- Radiological and Environmental Safety Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu, India
| | - Jayanthi Abraham
- Microbial Biotechnology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Anilkumar Gopinathan
- Molecular Endocrinology Laboratory, School of Biosciences and Technology, Vellore Institute of Technology, Vellore, Tamil Nadu, India
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2
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Cao X, Zheng J, Zhang R, Sun Y, Zhao M. Live-cell imaging of human apurinic/apyrimidinic endonuclease 1 in the nucleus and nucleolus using a chaperone@DNA probe. Nucleic Acids Res 2024; 52:e41. [PMID: 38554110 PMCID: PMC11077052 DOI: 10.1093/nar/gkae202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 03/07/2024] [Indexed: 04/01/2024] Open
Abstract
Human apurinic/apyrimidinic endonuclease 1 (APE1) plays crucial roles in repairing DNA damage and regulating RNA in the nucleus. However, direct visualization of nuclear APE1 in live cells remains challenging. Here, we report a chaperone@DNA probe for live-cell imaging of APE1 in the nucleus and nucleolus in real time. The probe is based on an assembly of phenylboronic acid modified avidin and biotin-labeled DNA containing an abasic site (named PB-ACP), which cleverly protects DNA from being nonspecifically destroyed while enabling targeted delivery of the probe to the nucleus. The PB-ACP construct specifically detects APE1 due to the high binding affinity of APE1 for both avidin and the abasic site in DNA. It is easy to prepare, biocompatible and allowing for long-term observation of APE1 activity. This molecular tool offers a powerful means to investigate the behavior of APE1 in the nuclei of various types of live cells, particularly for the development of improved cancer therapies targeting this protein.
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Affiliation(s)
- Xiangjian Cao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Jinghui Zheng
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ruilan Zhang
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Ying Sun
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Meiping Zhao
- Beijing National Laboratory for Molecular Sciences and MOE Key Laboratory of Bioorganic Chemistry and Molecular Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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3
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Sucharski F, Gallo G, Coelho C, Hardy L, Würtele M. Modeling the role of charged residues in thermophilic proteins by rotamer and dynamic cross correlation analysis. J Mol Model 2023; 29:132. [PMID: 37036538 DOI: 10.1007/s00894-023-05490-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 02/24/2023] [Indexed: 04/11/2023]
Abstract
Discerning the determinants of protein thermostability is very important both from the theoretical and applied perspective. Different lines of evidence seem to indicate that a dynamical network of salt bridges/charged residues plays a fundamental role in the thermostability of enzymes. In this work, we applied measures of dynamic variance, like the Gini coefficients, Kullback-Leibler (KL) divergence and dynamic cross correlation (DCC) coefficients to compare the behavior of 3 pairs of homologous proteins from the thermophilic bacterium Thermus thermophilus and mesophilic Escherichia coli. Molecular dynamic (MD) simulations of these proteins were performed at 303 K and 363 K. In the characterization of their side chain rotamer distributions, the corresponding Gini coefficients and KL-divergence both revealed significant correlations with temperature. Similarly, a DCC analysis revealed a higher trend to de-correlate the movement of charged residues at higher temperatures in the thermophilic proteins, when compared with their mesophilic homologues. These results highlight the importance of dynamic electrostatic network interactions for the thermostability of enzymes.
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Affiliation(s)
- Fernanda Sucharski
- Department of Science and Technology, Federal University of São Paulo, Talim 330, São José Dos Campos, São Paulo, 12231-280, Brazil
| | - Gloria Gallo
- Department of Science and Technology, Federal University of São Paulo, Talim 330, São José Dos Campos, São Paulo, 12231-280, Brazil
| | - Camila Coelho
- Department of Science and Technology, Federal University of São Paulo, Talim 330, São José Dos Campos, São Paulo, 12231-280, Brazil
| | - Leon Hardy
- Department of Physics, University of South Florida, Tampa, USA
| | - Martin Würtele
- Department of Science and Technology, Federal University of São Paulo, Talim 330, São José Dos Campos, São Paulo, 12231-280, Brazil.
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4
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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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5
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Garcia Gonzalez J, Hernandez FJ. Nuclease activity: an exploitable biomarker in bacterial infections. Expert Rev Mol Diagn 2022; 22:265-294. [PMID: 35240900 DOI: 10.1080/14737159.2022.2049249] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION In the increasingly challenging field of clinical microbiology, diagnosis is a cornerstone whose accuracy and timing are crucial for the successful management, therapy, and outcome of infectious diseases. Currently employed biomarkers of infectious diseases define the scope and limitations of diagnostic techniques. As such, expanding the biomarker catalog is crucial to address unmet needs and bring about novel diagnostic functionalities and applications. AREAS COVERED This review describes the extracellular nucleases of 15 relevant bacterial pathogens and discusses the potential use of nuclease activity as a diagnostic biomarker. Articles were searched for in PubMed using terms: "nuclease", "bacteria", "nuclease activity" or "biomarker". For overview sections, original and review articles between 2000 and 2019 were searched for using terms: "infections", "diagnosis", "bacterial", "burden", "challenges". Informative articles were selected. EXPERT OPINION Using the catalytic activity of nucleases offers new possibilities compared to established biomarkers. Nucleic acid activatable reporters in combination with different transduction platforms and delivery methods can be used to detect disease-associated nuclease activity patterns in vitro and in vivo for prognostic and diagnostic applications. Even when these patterns are not obvious or of unknown etiology, screening platforms could be used to identify new disease reporters.
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Affiliation(s)
- Javier Garcia Gonzalez
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Wallenberg Centre for Molecular Medicine (WCMM), Linköping, Sweden.,Nucleic Acids Technologies Laboratory (NAT-lab), Linköping University, Linköping, Sweden
| | - Frank J Hernandez
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden.,Wallenberg Centre for Molecular Medicine (WCMM), Linköping, Sweden.,Nucleic Acids Technologies Laboratory (NAT-lab), Linköping University, Linköping, Sweden
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6
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Liu TC, Guo KW, Chu JW, Hsiao YY. Understanding APE1 cellular functions by the structural preference of exonuclease activities. Comput Struct Biotechnol J 2021; 19:3682-3691. [PMID: 34285771 PMCID: PMC8258793 DOI: 10.1016/j.csbj.2021.06.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 12/17/2022] Open
Abstract
Mammalian apurinic/apyrimidinic (AP) endonuclease 1 (APE1) has versatile enzymatic functions, including redox, endonuclease, and exonuclease activities. APE1 is thus broadly associated with pathways in DNA repair, cancer cell growth, and drug resistance. Unlike its AP site-specific endonuclease activity in Base excision repair (BER), the 3′-5′ exonucleolytic cleavage of APE1 using the same active site exhibits complex substrate selection patterns, which are key to the biological functions. This work aims to integrate molecular structural information and biocatalytic properties to deduce the substrate recognition mechanism of APE1 as an exonuclease and make connection to its diverse functionalities in the cell. In particular, an induced space-filling model emerges in which a bridge-like structure is formed by Arg177 and Met270 (RM bridge) upon substrate binding, causing the active site to adopt a long and narrow product pocket for hosting the leaving group of an AP site or the 3′-end nucleotide. Rather than distinguishing bases as other exonucleases, the hydrophobicity and steric hindrance due to the APE1 product pocket provides selectivity for substrate structures, such as matched or mismatched blunt-ended dsDNA, recessed dsDNA, gapped dsDNA, and nicked dsDNA with 3′-end overhang shorter than 2 nucleotides. These dsDNAs are similar to the native substrates in BER proofreading, BER for trinucleotide repeats (TNR), Nucleotide incision repair (NIR), DNA single-strand breaks (SSB), SSB with damaged bases, and apoptosis. Integration of in vivo studies, in vitro biochemical assays, and structural analysis is thus essential for linking the APE1 exonuclease activity to the specific roles in cellular functions.
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Affiliation(s)
- Tung-Chang Liu
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan 30068, Taiwan
| | - Kai-Wei Guo
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan 30068, Taiwan
| | - Jhih-Wei Chu
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan 30068, Taiwan.,Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu, 30068, Taiwan.,Center For Intelligent Drug Systems and Smart Bio-devices (IDSB), National Yang Ming Chiao Tung University, Hsinchu, Taiwan
| | - Yu-Yuan Hsiao
- Institute of Molecular Medicine and Bioengineering, National Yang Ming Chiao Tung University, Hsinchu 30068, Taiwan.,Department of Biological Science and Technology, National Yang Ming Chiao Tung University, Hsinchu, Taiwan 30068, Taiwan.,Institute of Bioinformatics and Systems Biology, National Yang Ming Chiao Tung University, Hsinchu, 30068, Taiwan.,Center For Intelligent Drug Systems and Smart Bio-devices (IDSB), National Yang Ming Chiao Tung University, Hsinchu, Taiwan.,Drug Development and Value Creation Research Center, Center for Cancer Research, Kaohsiung Medical University, Kaohsiung, Taiwan
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7
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Dymova MA, Endutkin AV, Polunovsky VV, Zakabunin AI, Khrapov EA, Torgasheva NA, Yudkina AV, Mechetin GV, Filipenko ML, Zharkov DO. Characterization of Recombinant Endonuclease IV from Mycobacterium tuberculosis. Mol Biol 2021. [DOI: 10.1134/s0026893321020059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Zhang J, Wang S, Abee T, van der Veen S. Role of Base Excision Repair in Listeria monocytogenes DNA Stress Survival During Infections. J Infect Dis 2020; 223:721-732. [PMID: 32644146 DOI: 10.1093/infdis/jiaa412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 07/07/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Base excision repair (BER), consisting mostly of lesion-specific DNA glycosylases and apurinic/apyrimidinic (AP) endonucleases, is one of the most important DNA repair mechanisms for repair of single nucleobase lesions generated by reactive oxygen and nitrogen species as part of an immune response against bacterial infections. However, few studies have addressed the contribution of BER to bacterial virulence and Listeria monocytogenes BER has thus far remained completely uncharacterized. METHODS Analysis of the L. monocytogenes EGDe genome identified 7 DNA glycosylases (MutM, MutY, Nth, Tag, Mpg, Ung, and Ung2) and 2 apurinic/apyrimidinic endonucleases (Xth and Nfo) as part of BER. Markerless in-frame deletion mutants were generated for all 9 genes, and mutants were tested for DNA damage survival, mutagenesis, and the ability to colonize a mouse model of infection. RESULTS Distinct lesion-specific phenotypes were identified for all deletion mutants. Importantly, the Δnth, ΔmutY, and Δnfo mutants were significantly attenuated for virulence in the mouse model and showed much lower colonization of the liver and spleen or were unable to compete with the wild-type strain during in vivo competition assays. CONCLUSIONS Our results highlight the importance of BER for L. monocytogenes virulence and survival of DNA-damaging insults during host colonization.
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Affiliation(s)
- Juan Zhang
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Shuyi Wang
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Tjakko Abee
- Food Microbiology, Wageningen University & Research, Wageningen, The Netherlands
| | - Stijn van der Veen
- Department of Microbiology and Parasitology, School of Medicine, Zhejiang University, Hangzhou, China.,Department of Dermatology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China.,State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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9
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Mittal P, Sinha R, Kumar A, Singh P, Ngasainao MR, Singh A, Singh IK. Focusing on DNA Repair and Damage Tolerance Mechanisms in Mycobacterium tuberculosis: An Emerging Therapeutic Theme. Curr Top Med Chem 2020; 20:390-408. [PMID: 31924156 DOI: 10.2174/1568026620666200110114322] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 09/02/2019] [Accepted: 10/10/2019] [Indexed: 11/22/2022]
Abstract
Tuberculosis (TB) is one such disease that has become a nuisance in the world scenario and one of the most deadly diseases of the current times. The etiological agent of tuberculosis, Mycobacterium tuberculosis (M. tb) kills millions of people each year. Not only 1.7 million people worldwide are estimated to harbor M. tb in the latent form but also 5 to 15 percent of which are expected to acquire an infection during a lifetime. Though curable, a long duration of drug regimen and expense leads to low patient adherence. The emergence of multi-, extensive- and total- drug-resistant strains of M. tb further complicates the situation. Owing to high TB burden, scientists worldwide are trying to design novel therapeutics to combat this disease. Therefore, to identify new drug targets, there is a growing interest in targeting DNA repair pathways to fight this infection. Thus, this review aims to explore DNA repair and damage tolerance as an efficient target for drug development by understanding M. tb DNA repair and tolerance machinery and its regulation, its role in pathogenesis and survival, mutagenesis, and consequently, in the development of drug resistance.
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Affiliation(s)
- Pooja Mittal
- Molecular Biology Research Lab, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India
| | - Rajesh Sinha
- Molecular Biology Research Lab, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India
| | - Amit Kumar
- Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India
| | - Pooja Singh
- Public Health Research Institute, NJMS-Rutgers University, New Jersey, United States
| | - Moses Rinchui Ngasainao
- Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India
| | - Archana Singh
- Department of Botany, Hansraj College, University of Delhi, Delhi, 110007, India.,Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
| | - Indrakant K Singh
- Molecular Biology Research Lab, Department of Zoology, Deshbandhu College, University of Delhi, Kalkaji, New Delhi, 110019, India.,Department of Molecular Ecology, Max-Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, D-07745 Jena, Germany
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10
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Minias A, Brzostek A, Dziadek J. Targeting DNA Repair Systems in Antitubercular Drug Development. Curr Med Chem 2019; 26:1494-1505. [DOI: 10.2174/0929867325666180129093546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/01/2017] [Accepted: 11/01/2017] [Indexed: 11/22/2022]
Abstract
Infections with Mycobacterium tuberculosis, the causative agent of tuberculosis, are difficult to treat using currently available chemotherapeutics. Clinicians agree on the urgent need for novel drugs to treat tuberculosis. In this mini review, we summarize data that prompts the consideration of DNA repair-associated proteins as targets for the development of new antitubercular compounds. We discuss data, including gene expression data, that highlight the importance of DNA repair genes during the pathogenic cycle as well as after exposure to antimicrobials currently in use. Specifically, we report experiments on determining the essentiality of DNA repair-related genes. We report the availability of protein crystal structures and summarize discovered protein inhibitors. Further, we describe phenotypes of available gene mutants of M. tuberculosis and model organisms Mycobacterium bovis and Mycobacterium smegmatis. We summarize experiments regarding the role of DNA repair-related proteins in pathogenesis and virulence performed both in vitro and in vivo during the infection of macrophages and animals. We detail the role of DNA repair genes in acquiring mutations, which influence the rate of drug resistance acquisition.
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Affiliation(s)
- Alina Minias
- Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Anna Brzostek
- Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
| | - Jarosław Dziadek
- Laboratory of Genetics and Physiology of Mycobacterium, Institute of Medical Biology, Polish Academy of Sciences, Lodz, Poland
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11
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Evolution of endonuclease IV protein family: an in silico analysis. 3 Biotech 2019; 9:168. [PMID: 30997305 DOI: 10.1007/s13205-019-1696-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 03/28/2019] [Indexed: 02/07/2023] Open
Abstract
DNA repair is one of the key cellular events which balances between evolvability and integrity of the genome. Endonuclease IV enzymes are class II AP endonucleases under base excision repair pathway which act on abasic site and break the phosphodiester bond at the 5' side. The role and activity of endonuclease IV proteins vary among different organisms; even it is absent in higher eukaryotes. The evolution of this protein family was studied by analyzing all homologs of the endonuclease IV protein family through different in silico techniques including phylogenetic tree generation and model building. The sequence analysis revealed four consensus sequence motifs within the AP2EC domain which are functionally important and conserved throughout the evolution process. It was also observed that the species and endonuclease IV gene evolution shape up differently in most of the organisms. Presence of the mitochondria-targeted signal peptides in fungal species Saccharomyces and Coccidioides suggest a possible endosymbiotic transfer of endonuclease IV genes to lower eukaryotes. Evolutionary changes among various clades in the protein-based phylogenetic tree have been investigated by comparison of homology models which suggests the conservation of overall fold of endonuclease IV proteins except for few alterations in loop orientation in few clades.
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12
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Singh A. Guardians of the mycobacterial genome: A review on DNA repair systems in Mycobacterium tuberculosis. MICROBIOLOGY-SGM 2017; 163:1740-1758. [PMID: 29171825 DOI: 10.1099/mic.0.000578] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The genomic integrity of Mycobacterium tuberculosis is continuously threatened by the harsh survival conditions inside host macrophages, due to immune and antibiotic stresses. Faithful genome maintenance and repair must be accomplished under stress for the bacillus to survive in the host, necessitating a robust DNA repair system. The importance of DNA repair systems in pathogenesis is well established. Previous examination of the M. tuberculosis genome revealed homologues of almost all the major DNA repair systems, i.e. nucleotide excision repair (NER), base excision repair (BER), homologous recombination (HR) and non-homologous end joining (NHEJ). However, recent developments in the field have pointed to the presence of novel proteins and pathways in mycobacteria. Homologues of archeal mismatch repair proteins were recently reported in mycobacteria, a pathway previously thought to be absent. RecBCD, the major nuclease-helicase enzymes involved in HR in E. coli, were implicated in the single-strand annealing (SSA) pathway. Novel roles of archeo-eukaryotic primase (AEP) polymerases, previously thought to be exclusive to NHEJ, have been reported in BER. Many new proteins with a probable role in DNA repair have also been discovered. It is now realized that the DNA repair systems in M. tuberculosis are highly evolved and have redundant backup mechanisms to mend the damage. This review is an attempt to summarize our current understanding of the DNA repair systems in M. tuberculosis.
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Affiliation(s)
- Amandeep Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
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13
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Płociński P, Brissett NC, Bianchi J, Brzostek A, Korycka-Machała M, Dziembowski A, Dziadek J, Doherty AJ. DNA Ligase C and Prim-PolC participate in base excision repair in mycobacteria. Nat Commun 2017; 8:1251. [PMID: 29089537 PMCID: PMC5663958 DOI: 10.1038/s41467-017-01365-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 09/13/2017] [Indexed: 12/30/2022] Open
Abstract
Prokaryotic Ligase D is a conserved DNA repair apparatus processing DNA double-strand breaks in stationary phase. An orthologous Ligase C (LigC) complex also co-exists in many bacterial species but its function is unknown. Here we show that the LigC complex interacts with core BER enzymes in vivo and demonstrate that together these factors constitute an excision repair apparatus capable of repairing damaged bases and abasic sites. The polymerase component, which contains a conserved C-terminal structural loop, preferentially binds to and fills-in short gapped DNA intermediates with RNA and LigC ligates the resulting nicks to complete repair. Components of the LigC complex, like LigD, are expressed upon entry into stationary phase and cells lacking either of these pathways exhibit increased sensitivity to oxidising genotoxins. Together, these findings establish that the LigC complex is directly involved in an excision repair pathway(s) that repairs DNA damage with ribonucleotides during stationary phase. Ligase D is a conserved DNA repair protein complex that repairs double-strand breaks in stationary phase prokaryotes. Here the authors show that orthologous Ligase C has a role in base excision repair during stationary phase.
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Affiliation(s)
- Przemysław Płociński
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK.,Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232, Lodz, Poland
| | - Nigel C Brissett
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK
| | - Julie Bianchi
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK.,Department of Oncology-Pathology, Cancer Center Karolinska, Karolinska Institutet, R8:04, Karolinska Universitetssjukhuset Solna, 171 76, Stockholm, Sweden
| | - Anna Brzostek
- Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232, Lodz, Poland
| | | | - Andrzej Dziembowski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5A, 02-106, Warsaw, Poland
| | - Jarosław Dziadek
- Institute of Medical Biology, Polish Academy of Sciences, Lodowa 106, 93-232, Lodz, Poland
| | - Aidan J Doherty
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, BN1 9RQ, UK.
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14
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Zhang Y, Matsuzaka T, Yano H, Furuta Y, Nakano T, Ishikawa K, Fukuyo M, Takahashi N, Suzuki Y, Sugano S, Ide H, Kobayashi I. Restriction glycosylases: involvement of endonuclease activities in the restriction process. Nucleic Acids Res 2017; 45:1392-1403. [PMID: 28180312 PMCID: PMC5388411 DOI: 10.1093/nar/gkw1250] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/23/2016] [Accepted: 12/12/2016] [Indexed: 11/18/2022] Open
Abstract
All restriction enzymes examined are phosphodiesterases generating 3΄-OH and 5΄-P ends, but one restriction enzyme (restriction glycosylase) excises unmethylated bases from its recognition sequence. Whether its restriction activity involves endonucleolytic cleavage remains unclear. One report on this enzyme, R.PabI from a hyperthermophile, ascribed the breakage to high temperature while another showed its weak AP lyase activity generates atypical ends. Here, we addressed this issue in mesophiles. We purified R.PabI homologs from Campylobacter coli (R.CcoLI) and Helicobacter pylori (R.HpyAXII) and demonstrated their DNA cleavage, DNA glycosylase and AP lyase activities in vitro at 37°C. The AP lyase activity is more coupled with glycosylase activity in R.CcoLI than in R.PabI. R.CcoLI/R.PabI expression caused restriction of incoming bacteriophage/plasmid DNA and endogenous chromosomal DNA within Escherichia coli at 37°C. The R.PabI-mediated restriction was promoted by AP endonuclease action in vivo or in vitro. These results reveal the role of endonucleolytic DNA cleavage in restriction and yet point to diversity among the endonucleases. The cleaved ends are difficult to repair in vivo, which may indicate their biological significance. These results support generalization of the concept of restriction–modification system to the concept of self-recognizing epigenetic system, which combines any epigenetic labeling and any DNA damaging.
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Affiliation(s)
- Yingbiao Zhang
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
| | - Tomoyuki Matsuzaka
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University Higashi-Hiroshima 739-8526, Japan
| | - Hirokazu Yano
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
- Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8572, Japan
| | - Yoshikazu Furuta
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
- Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Toshiaki Nakano
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University Higashi-Hiroshima 739-8526, Japan
| | - Ken Ishikawa
- National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Masaki Fukuyo
- Department of Molecular Oncology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | - Noriko Takahashi
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
- Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
| | - Sumio Sugano
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
| | - Hiroshi Ide
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University Higashi-Hiroshima 739-8526, Japan
| | - Ichizo Kobayashi
- Department of Computational Biology and Medical Sciences (formerly Department of Medical Genome Sciences), Graduate School of Frontier Sciences, University of Tokyo, Tokyo 108-8639, Japan
- Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
- Faculty of Medicine, Kyorin University, Mitaka, Tokyo 181-8611, Japan
- Institut for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette 91198, France
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru 560 064, India
- To whom correspondence should be addressed. Tel: +81 90 2487 7510; ; ;
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15
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Dang G, Cao J, Cui Y, Song N, Chen L, Pang H, Liu S. Characterization of Rv0888, a Novel Extracellular Nuclease from Mycobacterium tuberculosis. Sci Rep 2016; 6:19033. [PMID: 26742696 PMCID: PMC4733049 DOI: 10.1038/srep19033] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 12/02/2015] [Indexed: 02/07/2023] Open
Abstract
Bacterial extracellular nucleases play important roles in virulence, biofilm formation, utilization of extracellular DNA as a nutrient, and degradation of neutrophil DNA extracellular traps. However, there is no current data available for extracellular nucleases derived from M. tuberculosis. Herein, we have identified and characterized Rv0888, an extracellular nuclease in M. tuberculosis. The protein was overexpressed in E. coli, and the purified Rv0888 protein was found to require divalent cations for activity, with an optimal temperature and pH of 41 °C and 6.5, respectively. Further results demonstrated that Rv0888 nuclease activity could be inhibited by four Chinese medicine monomers. Based on sequence analysis, Rv0888 nuclease exhibited no homology with any known extracellular nucleases, indicating that Rv0888 is a novel nuclease. Site-directed mutagenesis studies revealed that the H353, D387, and D438 residues play catalytic roles in Rv0888. In vivo infection studies confirmed that Rv0888 is required for infection and is related to pathogenicity, as the persistent ability of recombinant Mycobacterium smegmatis (rMS) Rv0888NS/MS and Rv0888S/MS is significantly higher than pMV262/MS in the lung tissue, and the Rv0888NS/MS and Rv0888S/MS could produce pathological changes in the mice lung. These results show that Rv0888 is relevant to pathogenicity of M. tuberculosis.
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Affiliation(s)
- Guanghui Dang
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Jun Cao
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Yingying Cui
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Ningning Song
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Liping Chen
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
| | - Hai Pang
- School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Siguo Liu
- Division of Bacterial Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, 427 Maduan Street, Nangang Dist, Harbin 15000, PR China
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16
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Khanam T, Rai N, Ramachandran R. Mycobacterium tuberculosis class II apurinic/apyrimidinic-endonuclease/3'-5' exonuclease III exhibits DNA regulated modes of interaction with the sliding DNA β-clamp. Mol Microbiol 2015; 98:46-68. [PMID: 26103519 DOI: 10.1111/mmi.13102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2015] [Indexed: 11/30/2022]
Abstract
The class-II AP-endonuclease (XthA) acts on abasic sites of damaged DNA in bacterial base excision repair. We identified that the sliding DNA β-clamp forms in vivo and in vitro complexes with XthA in Mycobacterium tuberculosis. A novel 239 QLRFPKK245 motif in the DNA-binding domain of XthA was found to be important for the interactions. Likewise, the peptide binding-groove (PBG) and the C-terminal of β-clamp located on different domains interact with XthA. The β-clamp-XthA complex can be disrupted by clamp binding peptides and also by a specific bacterial clamp inhibitor that binds at the PBG. We also identified that β-clamp stimulates the activities of XthA primarily by increasing its affinity for the substrate and its processivity. Additionally, loading of the β-clamp onto DNA is required for activity stimulation. A reduction in XthA activity stimulation was observed in the presence of β-clamp binding peptides supporting that direct interactions between the proteins are necessary to cause stimulation. Finally, we found that in the absence of DNA, the PBG located on the second domain of the β-clamp is important for interactions with XthA, while the C-terminal domain predominantly mediates functional interactions in the substrate's presence.
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Affiliation(s)
- Taran Khanam
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
| | - Niyati Rai
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
| | - Ravishankar Ramachandran
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, Lucknow, Uttar Pradesh, 226031, India
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17
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Characterization of DNA substrate specificities of apurinic/apyrimidinic endonucleases from Mycobacterium tuberculosis. DNA Repair (Amst) 2015; 33:1-16. [PMID: 26043425 DOI: 10.1016/j.dnarep.2015.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/19/2015] [Accepted: 05/18/2015] [Indexed: 11/24/2022]
Abstract
Apurinic/apyrimidinic (AP) endonucleases are key enzymes involved in the repair of abasic sites and DNA strand breaks. Pathogenic bacteria Mycobacterium tuberculosis contains two AP endonucleases: MtbXthA and MtbNfo members of the exonuclease III and endonuclease IV families, which are exemplified by Escherichia coli Xth and Nfo, respectively. It has been shown that both MtbXthA and MtbNfo contain AP endonuclease and 3'→5' exonuclease activities. However, it remains unclear whether these enzymes hold 3'-repair phosphodiesterase and nucleotide incision repair (NIR) activities. Here, we report that both mycobacterial enzymes have 3'-repair phosphodiesterase and 3'-phosphatase, and MtbNfo contains in addition a very weak NIR activity. Interestingly, depending on pH, both enzymes require different concentrations of divalent cations: 0.5mM MnCl2 at pH 7.6 and 10 mM at pH 6.5. MtbXthA requires a low ionic strength and 37 °C, while MtbNfo requires high ionic strength (200 mM KCl) and has a temperature optimum at 60 °C. Point mutation analysis showed that D180 and N182 in MtbXthA and H206 and E129 in MtbNfo are critical for enzymes activities. The steady-state kinetic parameters indicate that MtbXthA removes 3'-blocking sugar-phosphate and 3'-phosphate moieties at DNA strand breaks with an extremely high efficiency (kcat/KM=440 and 1280 μM(-1)∙min(-1), respectively), while MtbNfo exhibits much lower 3'-repair activities (kcat/KM=0.26 and 0.65 μM(-1)∙min(-1), respectively). Surprisingly, both MtbXthA and MtbNfo exhibited very weak AP site cleavage activities, with kinetic parameters 100- and 300-fold lower, respectively, as compared with the results reported previously. Expression of MtbXthA and MtbNfo reduced the sensitivity of AP endonuclease-deficient E. coli xth nfo strain to methylmethanesulfonate and H2O2 to various degrees. Taken together, these data establish the DNA substrate specificity of M. tuberculosis AP endonucleases and suggest their possible role in the repair of oxidative DNA damage generated by endogenous and host- imposed factors.
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18
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Khanam T, Shukla A, Rai N, Ramachandran R. Critical determinants for substrate recognition and catalysis in the M. tuberculosis class II AP-endonuclease/3'-5' exonuclease III. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:505-16. [PMID: 25748880 DOI: 10.1016/j.bbapap.2015.02.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/02/2015] [Accepted: 02/25/2015] [Indexed: 01/13/2023]
Abstract
The Mycobacterium tuberculosis AP-endonuclease/3'-5' exodeoxyribonuclease (MtbXthA) is an important player in DNA base excision repair (BER). We demonstrate that the enzyme has robust apurinic/apyrimidinic (AP) endonuclease activity, 3'-5' exonuclease, phosphatase, and phosphodiesterase activities. The enzyme functions as an AP-endonuclease at high ionic environments, while the 3'-5'-exonuclease activity is predominant at low ionic environments. Our molecular modelling and mutational experiments show that E57 and D251 are critical for catalysis. Although nicked DNA and gapped DNA are fair substrates of MtbXthA, the gap-size did not affect the excision activity and furthermore, a substrate with a recessed 3'-end is preferred. To understand the determinants of abasic-site recognition, we examined the possible roles of (i) the base opposite the abasic site, (ii) the abasic ribose ring itself, (iii) local distortions in the AP-site, and (iv) conserved residues located near the active site. Our experiments demonstrate that the first three determinants do not play a role in MtbXthA, and in fact the enzyme exhibits robust endonucleolytic activity against single-stranded AP DNA also. Regarding the fourth determinant, it is known that the catalytic-site of AP endonucleases is surrounded by conserved aromatic residues and intriguingly, the exact residues that are directly involved in abasic site recognition vary with the individual proteins. We therefore, used a combination of mutational analysis, kinetic assays, and structure-based modelling, to identify that Y237, supported by Y137, mediates the formation of the MtbXthA-AP-DNA complex and AP-site incision.
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Affiliation(s)
- Taran Khanam
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Lucknow, Uttar Pradesh 226031, India
| | - Ankita Shukla
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Lucknow, Uttar Pradesh 226031, India
| | - Niyati Rai
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Lucknow, Uttar Pradesh 226031, India
| | - Ravishankar Ramachandran
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Lucknow, Uttar Pradesh 226031, India.
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19
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van der Veen S, Tang CM. The BER necessities: the repair of DNA damage in human-adapted bacterial pathogens. Nat Rev Microbiol 2015; 13:83-94. [PMID: 25578955 DOI: 10.1038/nrmicro3391] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
During colonization and disease, bacterial pathogens must survive the onslaught of the host immune system. A key component of the innate immune response is the generation of reactive oxygen and nitrogen species by phagocytic cells, which target and disrupt pathogen molecules, particularly DNA, and the base excision repair (BER) pathway is the most important mechanism for the repair of such oxidative DNA damage. In this Review, we discuss how the human-specific pathogens Mycobacterium tuberculosis, Helicobacter pylori and Neisseria meningitidis have evolved specialized mechanisms of DNA repair, particularly their BER pathways, compared with model organisms such as Escherichia coli. This specialization in DNA repair is likely to reflect the distinct niches occupied by these important human pathogens in the host.
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Affiliation(s)
- Stijn van der Veen
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford, OX1 3RE, UK
| | - Christoph M Tang
- Sir William Dunn School of Pathology, South Parks Road, University of Oxford, Oxford, OX1 3RE, UK
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20
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Puri RV, Reddy PV, Tyagi AK. Apurinic/apyrimidinic endonucleases of Mycobacterium tuberculosis protect against DNA damage but are dispensable for the growth of the pathogen in guinea pigs. PLoS One 2014; 9:e92035. [PMID: 24800740 PMCID: PMC4011885 DOI: 10.1371/journal.pone.0092035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 02/19/2014] [Indexed: 12/31/2022] Open
Abstract
In host cells, Mycobacterium tuberculosis encounters an array of reactive molecules capable of damaging its genome. Non-bulky DNA lesions are the most common damages produced on the exposure of the pathogen to reactive species and base excision repair (BER) pathway is involved in the repair of such damage. During BER, apurinic/apyrimidinic (AP) endonuclease enzymes repair the abasic sites that are generated after spontaneous DNA base loss or by the action of DNA glycosylases, which if left unrepaired lead to inhibition of replication and transcription. However, the role of AP endonucleases in imparting protection against DNA damage and in the growth and pathogenesis of M.tuberculosis has not yet been elucidated. To demonstrate the biological significance of these enzymes in M.tuberculosis, it would be desirable to disrupt the relevant genes and evaluate the resulting mutants for their ability to grow in the host and cause disease. In this study, we have generated M.tuberculosis mutants of the base excision repair (BER) system, disrupted in either one (MtbΔend or MtbΔxthA) or both the AP endonucleases (MtbΔendΔxthA). We demonstrate that these genes are crucial for bacteria to withstand alkylation and oxidative stress in vitro. In addition, the mutant disrupted in both the AP endonucleases (MtbΔendΔxthA) exhibited a significant reduction in its ability to survive inside human macrophages. However, infection of guinea pigs with either MtbΔend or MtbΔxthA or MtbΔendΔxthA resulted in the similar bacillary load and pathological damage in the organs as observed in the case of infection with wild-type M.tuberculosis. The implications of these observations are discussed.
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Affiliation(s)
- Rupangi Verma Puri
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - P. Vineel Reddy
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
| | - Anil K. Tyagi
- Department of Biochemistry, University of Delhi South Campus, New Delhi, India
- * E-mail:
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