1
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Nautiyal A, Thakur M. Prokaryotic DNA Crossroads: Holliday Junction Formation and Resolution. ACS OMEGA 2024; 9:12515-12538. [PMID: 38524412 PMCID: PMC10956419 DOI: 10.1021/acsomega.3c09866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 02/04/2024] [Accepted: 02/09/2024] [Indexed: 03/26/2024]
Abstract
Cells are continually exposed to a multitude of internal and external stressors, which give rise to various types of DNA damage. To protect the integrity of their genetic material, cells are equipped with a repertoire of repair proteins that engage in various repair mechanisms, facilitated by intricate networks of protein-protein and protein-DNA interactions. Among these networks is the homologous recombination (HR) system, a molecular repair mechanism conserved in all three domains of life. On one hand, HR ensures high-fidelity, template-dependent DNA repair, while on the other hand, it results in the generation of combinatorial genetic variations through allelic exchange. Despite substantial progress in understanding this pathway in bacteria, yeast, and humans, several critical questions remain unanswered, including the molecular processes leading to the exchange of DNA segments, the coordination of protein binding, conformational switching during branch migration, and the resolution of Holliday Junctions (HJs). This Review delves into our current understanding of the HR pathway in bacteria, shedding light on the roles played by various proteins or their complexes at different stages of HR. In the first part of this Review, we provide a brief overview of the end resection processes and the strand-exchange reaction, offering a concise depiction of the mechanisms that culminate in the formation of HJs. In the latter half, we expound upon the alternative methods of branch migration and HJ resolution more comprehensively and holistically, considering the historical research timelines. Finally, when we consolidate our knowledge about HR within the broader context of genome replication and the emergence of resistant species, it becomes evident that the HR pathway is indispensable for the survival of bacteria in diverse ecological niches.
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Affiliation(s)
- Astha Nautiyal
- Department
of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - Manoj Thakur
- Sri
Venkateswara College, Benito Juarez Road, University of Delhi, New Delhi 110021, India
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2
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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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3
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Paul A, Mishra A, Surolia A, Vijayan M. Structural studies on
M. tuberculosis
argininosuccinate lyase and its liganded complex: Insights into catalytic mechanism. IUBMB Life 2019; 71:643-652. [DOI: 10.1002/iub.2000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 12/17/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Anju Paul
- Molecular Biophysics UnitIndian Institute of Science Bangalore India
| | - Archita Mishra
- Molecular Biophysics UnitIndian Institute of Science Bangalore India
| | - Avadhesha Surolia
- Molecular Biophysics UnitIndian Institute of Science Bangalore India
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4
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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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5
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Arif SM, Varshney U, Vijayan M. Hydrolysis of diadenosine polyphosphates. Exploration of an additional role of Mycobacterium smegmatis MutT1. J Struct Biol 2017; 199:165-176. [PMID: 28705712 DOI: 10.1016/j.jsb.2017.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/06/2017] [Accepted: 07/08/2017] [Indexed: 10/19/2022]
Abstract
Diadenosine polyphosphates (ApnA, n=2-6), particularly Ap4A, are involved in several important physiological processes. The substantial sequence identity of the Nudix hydrolase domain (domain 1) of Mycobacterium smegmatis MutT1 (MsMutT1) with a known Ap4A hydrolase suggested that MsMutT1 could also hydrolyse diadenosine polyphosphates. Biochemical experiments yielded results in conformity with this suggestion, with Ap4A as the best among the substrates. ATP is a product in all experiments; small amounts of ADP were also observed in the experiments involving Ap4A and Ap6A. Hydrolysis was inhibited by fluoride ions in all cases. The mechanism of action and its inhibition in relation to ApnA were explored through the X-ray analysis of the crystals of the MsMutT1 complexes with Ap5A; Ap5A and MnCl2; Ap4A; ATP; and ATP.NaF.MgCl2. The aggregation pattern of molecules in the first four crystals is similar to that found in a majority of MsMutT1-NTP crystals. Substrate molecules occupy the primary binding site and ATP occupies a site at an intermolecular interface, in the first two. ATP occupies both the sites in the third and fourth crystal. The protein-ligand interactions observed in these crystal structures lead to an explanation of the molecular mechanism of hydrolysis of ApnA by MsMutT1. The fifth crystal exhibits a new packing arrangement. The structure of the complex provides an explanation for the fluoride inhibition of the activity of the enzyme. It would thus appear that MutT1 has a major role involving the hydrolysis of diadenosine polyphosphates, which could be elucidated at the molecular level.
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Affiliation(s)
- S M Arif
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - U Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - M Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India.
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6
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Chandran AV, Jayanthi S, Vijayan M. Structure and interactions of RecA: plasticity revealed by molecular dynamics simulations. J Biomol Struct Dyn 2017; 36:98-111. [PMID: 28049371 DOI: 10.1080/07391102.2016.1268975] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Eleven independent simulations, each involving three consecutive molecules in the RecA filament, carried out on the protein from Mycobacterium tuberculosis, Mycobacterium smegmatis and Escherichia coli and their Adenosine triphosphate (ATP) complexes, provide valuable information which is complementary to that obtained from crystal structures, in addition to confirming the robust common structural framework within which RecA molecules from different eubacteria function. Functionally important loops, which are largely disordered in crystal structures, appear to adopt in each simulation subsets of conformations from larger ensembles. The simulations indicate the possibility of additional interactions involving the P-loop which remains largely invariant. The phosphate tail of the ATP is firmly anchored on the loop while the nucleoside moiety exhibits substantial structural variability. The most important consequence of ATP binding is the movement of the 'switch' residue. The relevant simulations indicate the feasibility of a second nucleotide binding site, but the pathway between adjacent molecules in the filament involving the two nucleotide binding sites appears to be possible only in the mycobacterial proteins.
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Affiliation(s)
- Anu V Chandran
- a Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India
| | - S Jayanthi
- a Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India
| | - M Vijayan
- a Molecular Biophysics Unit , Indian Institute of Science , Bangalore 560012 , India
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7
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Singh A, Bhagavat R, Vijayan M, Chandra N. A comparative analysis of the DNA recombination repair pathway in mycobacterial genomes. Tuberculosis (Edinb) 2016; 99:109-119. [PMID: 27450012 DOI: 10.1016/j.tube.2016.04.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/19/2016] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
In prokaryotes, repair by homologous recombination provides a major means to reinstate the genetic information lost in DNA damage. Recombination repair pathway in mycobacteria has multiple differences as compared to that in Escherichia coli. Of about 20 proteins known to be involved in the pathway, a set of 9 proteins, namely, RecF, RecO, RecR, RecA, SSBa, RuvA, RuvB and RuvC was found to be indispensable among the 43 mycobacterial strains. A domain level analysis indicated that most domains involved in recombination repair are unique to these proteins and are present as single copies in the genomes. Synteny analysis reveals that the gene order of proteins involved in the pathway is not conserved, suggesting that they may be regulated differently in different species. Sequence conservation among the same protein from different strains suggests the importance of RecO-RecA and RecFOR-RecA presynaptic pathways in the repair of double strand-breaks and single strand-breaks respectively. New annotations obtained from the analysis, include identification of a protein with a probable Holliday junction binding role present in 41 mycobacterial genomes and that of a RecB-like nuclease, containing a cas4 domain, present in 42 genomes. New insights into the binding of small molecules to the relevant proteins are provided by binding pocket analysis using three dimensional structural models. Analysis of the various features of the recombination repair pathway, presented here, is likely to provide a framework for further exploring stress response and emergence of drug resistance in mycobacteria.
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Affiliation(s)
- Amandeep Singh
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Raghu Bhagavat
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - M Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, Karnataka, India
| | - Nagasuma Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, Karnataka, India.
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8
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Chandran AV, Prabu JR, Nautiyal A, Patil KN, Muniyappa K, Vijayan M. Structural studies on Mycobacterium tuberculosis RecA: molecular plasticity and interspecies variability. J Biosci 2015; 40:13-30. [PMID: 25740138 DOI: 10.1007/s12038-014-9497-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Structures of crystals of Mycobacterium tuberculosis RecA, grown and analysed under different conditions, provide insights into hitherto underappreciated details of molecular structure and plasticity. In particular, they yield information on the invariant and variable features of the geometry of the P-loop, whose binding to ATP is central for all the biochemical activities of RecA. The strengths of interaction of the ligands with the P-loop reveal significant differences. This in turn affects the magnitude of the motion of the 'switch' residue, Gln195 in M. tuberculosis RecA, which triggers the transmission of ATP-mediated allosteric information to the DNA binding region. M. tuberculosis RecA is substantially rigid compared with its counterparts from M. smegmatis and E. coli, which exhibit concerted internal molecular mobility. The interspecies variability in the plasticity of the two mycobacterial proteins is particularly surprising as they have similar sequence and 3D structure. Details of the interactions of ligands with the protein, characterized in the structures reported here, could be useful for design of inhibitors against M. tuberculosis RecA.
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Affiliation(s)
- Anu V Chandran
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012
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9
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Badawi M, Giraud I, Vavre F, Grève P, Cordaux R. Signs of neutralization in a redundant gene involved in homologous recombination in Wolbachia endosymbionts. Genome Biol Evol 2014; 6:2654-64. [PMID: 25230723 PMCID: PMC4224334 DOI: 10.1093/gbe/evu207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Genomic reduction in bacterial endosymbionts occurs through large genomic deletions and long-term accumulation of mutations. The latter process involves successive steps including gene neutralization, pseudogenization, and gradual erosion until complete loss. Although many examples of pseudogenes at various levels of degradation have been reported, neutralization cases are scarce because of the transient nature of the process. Gene neutralization may occur due to relaxation of selection in nonessential genes, for example, those involved in redundant functions. Here, we report an example of gene neutralization in the homologous recombination (HR) pathway of Wolbachia, a bacterial endosymbiont of arthropods and nematodes. The HR pathway is often depleted in endosymbiont genomes, but it is apparently intact in some Wolbachia strains. Analysis of 12 major HR genes showed that they have been globally under strong purifying selection during the evolution of Wolbachia strains hosted by arthropods, supporting the evolutionary importance of the HR pathway for these Wolbachia genomes. However, we detected signs of recent neutralization of the ruvA gene in a subset of Wolbachia strains, which might be related to an ancestral, clade-specific amino acid change that impaired DNA-binding activity. Strikingly, RuvA is part of the RuvAB complex involved in branch migration, whose function overlaps with the RecG helicase. Although ruvA is experiencing neutralization, recG is under strong purifying selection. Thus, our high phylogenetic resolution suggests that we identified a rare example of targeted neutralization of a gene involved in a redundant function in an endosymbiont genome.
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Affiliation(s)
- Myriam Badawi
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Poitiers, France
| | - Isabelle Giraud
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Poitiers, France
| | - Fabrice Vavre
- Université de Lyon, UMR CNRS 5558 Biométrie et Biologie Evolutive, Villeurbanne, France
| | - Pierre Grève
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Poitiers, France
| | - Richard Cordaux
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, Poitiers, France
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10
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Selvaraj M, Govindan A, Seshadri A, Dubey B, Varshney U, Vijayan M. Molecular flexibility of Mycobacterium tuberculosis ribosome recycling factor and its functional consequences: an exploration involving mutants. J Biosci 2014; 38:845-55. [PMID: 24296887 DOI: 10.1007/s12038-013-9381-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Internal mobility of the two domain molecule of ribosome recycling factor (RRF) is known to be important for its action. Mycobacterium tuberculosis RRF does not complement E. coli for its deficiency of RRF (in the presence of E. coli EF-G alone). Crystal structure had revealed higher rigidity of the M. tuberculosis RRF due to the presence of additional salt bridges between domains. Two inter-domain salt bridges and one between the linker region and the domain containing C-terminal residues were disrupted by appropriate mutations. Except for a C-terminal deletion mutant, all mutants showed RRF activity in E. coli when M. tuberculosis EF-G was also co-expressed. The crystal structures of the point mutants, that of the C-terminal deletion mutant and that of the protein grown in the presence of a detergent, were determined. The increased mobility resulting from the disruption of the salt bridge involving the hinge region allows the appropriate mutant to weakly complement E. coli for its deficiency of RRF even in the absence of simultaneous expression of the mycobacterial EF-G. The loss of activity of the C-terminal deletion mutant appears to be partly due to the rigidification of the molecule consequent to changes in the hinge region.
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Affiliation(s)
- M Selvaraj
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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11
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Patra D, Mishra P, Surolia A, Vijayan M. Structure, interactions and evolutionary implications of a domain-swapped lectin dimer from Mycobacterium smegmatis. Glycobiology 2014; 24:956-65. [DOI: 10.1093/glycob/cwu059] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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12
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Arif SM, Sang PB, Varshney U, Vijayan M. Crystallization and preliminary X-ray characterization of MutT2, MSMEG_5148 from Mycobacterium smegmatis. Acta Crystallogr F Struct Biol Commun 2014; 70:190-2. [PMID: 24637753 PMCID: PMC3936434 DOI: 10.1107/s2053230x13033906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/15/2013] [Indexed: 11/10/2022] Open
Abstract
Crystallization of MutT2, MSMEG_5148 from Mycobacterium smegmatis, has been carried out and the crystals have been characterized using X-ray diffraction. Matthews coefficient calculation suggests the possibility of one protein molecule in the asymmetric unit of the orthorhombic unit cell, space group P2(1)2(1)2 or P2(1)22. Solution of the structure of the protein by molecular replacement using the known three-dimensional structure of a bacterial Nudix hydrolase is envisaged.
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Affiliation(s)
- S. M. Arif
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - P. B. Sang
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - U. Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - M. Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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13
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Paul A, Mishra A, Surolia A, Vijayan M. Cloning, expression, purification, crystallization and preliminary X-ray studies of argininosuccinate lyase (Rv1659) from Mycobacterium tuberculosis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:1422-4. [PMID: 24316845 PMCID: PMC3855735 DOI: 10.1107/s1744309113031138] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 11/12/2013] [Indexed: 11/10/2022]
Abstract
The last enzyme in the arginine-biosynthesis pathway, argininosuccinate lyase, from Mycobacterium tuberculosis has been cloned, expressed, purified and crystallized, and preliminary X-ray studies have been carried out on the crystals. The His-tagged tetrameric enzyme with a subunit molecular weight of 50.9 kDa crystallized with two tetramers in the asymmetric unit of the orthorhombic unit cell, space group P2(1)2(1)2(1). Molecular-replacement calculations and self-rotation calculations confirmed the space group and the tetrameric nature of the molecule.
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Affiliation(s)
- A. Paul
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - A. Mishra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - A. Surolia
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - M. Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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14
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Abhinav KV, Sharma A, Vijayan M. Identification of mycobacterial lectins from genomic data. Proteins 2012. [DOI: 10.1002/prot.24219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Crowding, molecular volume and plasticity: An assessment involving crystallography, NMR and simulations. J Biosci 2012; 37:953-63. [DOI: 10.1007/s12038-012-9276-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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16
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Arif SM, Patil AG, Varshney U, Vijayan M. Crystallization and preliminary X-ray studies of MutT1 (MSMEG_2390) from Mycobacterium smegmatis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:1214-6. [PMID: 23027750 PMCID: PMC3497982 DOI: 10.1107/s1744309112035804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/14/2012] [Indexed: 11/10/2022]
Abstract
MutT1 (MSMEG_2390) from Mycobacterium smegmatis has been crystallized and the crystals have been characterized using X-ray diffraction. The crystals belonged to space group P2(1)2(1)2(1). The Matthews coefficient suggested the possibility of one protein molecule in the asymmetric unit of the orthorhombic unit cell. Solution of the structure using the known three-dimensional structure of a bacterial MutT1 is anticipated.
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Affiliation(s)
- S. M. Arif
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - A. G. Patil
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - U. Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - M. Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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17
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Khanduja JS, Muniyappa K. Functional analysis of DNA replication fork reversal catalyzed by Mycobacterium tuberculosis RuvAB proteins. J Biol Chem 2012; 287:1345-60. [PMID: 22094465 PMCID: PMC3256873 DOI: 10.1074/jbc.m111.304741] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 11/14/2011] [Indexed: 11/06/2022] Open
Abstract
Initially discovered in Escherichia coli, RuvAB proteins are ubiquitous in bacteria and play a dual role as molecular motor proteins responsible for branch migration of the Holliday junction(s) and reversal of stalled replication forks. Despite mounting genetic evidence for a crucial role of RuvA and RuvB proteins in reversal of stalled replication forks, the mechanistic aspects of this process are still not fully understood. Here, we elucidate the ability of Mycobacterium tuberculosis RuvAB (MtRuvAB) complex to catalyze the reversal of replication forks using a range of DNA replication fork substrates. Our studies show that MtRuvAB, unlike E. coli RuvAB, is able to drive replication fork reversal via the formation of Holliday junction intermediates, suggesting that RuvAB-catalyzed fork reversal involves concerted unwinding and annealing of nascent leading and lagging strands. We also demonstrate the reversal of replication forks carrying hemi-replicated DNA, indicating that MtRuvAB complex-catalyzed fork reversal is independent of symmetry at the fork junction. The fork reversal reaction catalyzed by MtRuvAB is coupled to ATP hydrolysis, is processive, and culminates in the formation of an extended reverse DNA arm. Notably, we found that sequence heterology failed to impede the fork reversal activity of MtRuvAB. We discuss the implications of these results in the context of recognition and processing of varied types of replication fork structures by RuvAB proteins.
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Affiliation(s)
- Jasbeer Singh Khanduja
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - K. Muniyappa
- From the Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
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18
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Arora A, Chandra NR, Das A, Gopal B, Mande SC, Prakash B, Ramachandran R, Sankaranarayanan R, Sekar K, Suguna K, Tyagi AK, Vijayan M. Structural biology of Mycobacterium tuberculosis proteins: The Indian efforts. Tuberculosis (Edinb) 2011; 91:456-68. [DOI: 10.1016/j.tube.2011.03.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Revised: 03/15/2011] [Accepted: 03/16/2011] [Indexed: 01/23/2023]
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19
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Chetnani B, Kumar P, Abhinav KV, Chhibber M, Surolia A, Vijayan M. Location and conformation of pantothenate and its derivatives in Mycobacterium tuberculosis pantothenate kinase: insights into enzyme action. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2011; 67:774-83. [PMID: 21904030 DOI: 10.1107/s0907444911024462] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2011] [Accepted: 06/22/2011] [Indexed: 11/10/2022]
Abstract
Previous studies of complexes of Mycobacterium tuberculosis PanK (MtPanK) with nucleotide diphosphates and nonhydrolysable analogues of nucleoside triphosphates in the presence or the absence of pantothenate established that the enzyme has dual specificity for ATP and GTP, revealed the unusual movement of ligands during enzyme action and provided information on the effect of pantothenate on the location and conformation of the nucleotides at the beginning and the end of enzyme action. The X-ray analyses of the binary complexes of MtPanK with pantothenate, pantothenol and N-nonylpantothenamide reported here demonstrate that in the absence of nucleotide these ligands occupy, with a somewhat open conformation, a location similar to that occupied by phosphopantothenate in the `end' complexes, which differs distinctly from the location of pantothenate in the closed conformation in the ternary `initiation' complexes. The conformation and the location of the nucleotide were also different in the initiation and end complexes. An invariant arginine appears to play a critical role in the movement of ligands that takes place during enzyme action. The work presented here completes the description of the locations and conformations of nucleoside diphosphates and triphosphates and pantothenate in different binary and ternary complexes, and suggests a structural rationale for the movement of ligands during enzyme action. The present investigation also suggests that N-alkylpantothenamides could be phosphorylated by the enzyme in the same manner as pantothenate.
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Affiliation(s)
- Bhaskar Chetnani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore
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Patra D, Sharma A, Chandran D, Vijayan M. Cloning, expression, purification, crystallization and preliminary X-ray studies of the mannose-binding lectin domain of MSMEG_3662 from Mycobacterium smegmatis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:596-9. [PMID: 21543870 PMCID: PMC3087649 DOI: 10.1107/s1744309111009547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Accepted: 03/13/2011] [Indexed: 11/10/2022]
Abstract
The mannose-binding lectin domain of MSMEG_3662 from Mycobacterium smegmatis has been cloned, expressed, purified and crystallized and the crystals have been characterized using X-ray diffraction. The Matthews coefficient suggests the possibility of two lectin domains in the triclinic cell. The amino-acid sequence of the domain indicates structural similarity to well characterized β-prism II fold lectins.
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Affiliation(s)
- Dhabaleswar Patra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Alok Sharma
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Divya Chandran
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - Mamannamana Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Chandran AV, Prabu JR, Manjunath GP, Patil KN, Muniyappa K, Vijayan M. Crystallization and preliminary X-ray studies of the C-terminal domain of Mycobacterium tuberculosis LexA. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1093-5. [PMID: 20823535 PMCID: PMC2935236 DOI: 10.1107/s174430911003068x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 08/01/2010] [Indexed: 11/10/2022]
Abstract
The C-terminal domain of Mycobacterium tuberculosis LexA has been crystallized in two different forms. The form 1 and form 2 crystals belonged to space groups P3(1)21 and P3(1), respectively. Form 1 contains one domain in the asymmetric unit, while form 2 contains six crystallographically independent domains. The structures have been solved by molecular replacement.
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Affiliation(s)
- Anu V. Chandran
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - J. Rajan Prabu
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - G. P. Manjunath
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | | | - K. Muniyappa
- Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India
| | - M. Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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Chetnani B, Kumar P, Surolia A, Vijayan M. M. tuberculosis pantothenate kinase: dual substrate specificity and unusual changes in ligand locations. J Mol Biol 2010; 400:171-85. [PMID: 20451532 DOI: 10.1016/j.jmb.2010.04.064] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 04/29/2010] [Accepted: 04/30/2010] [Indexed: 12/19/2022]
Abstract
Kinetic measurements of enzyme activity indicate that type I pantothenate kinase from Mycobacterium tuberculosis has dual substrate specificity for ATP and GTP, unlike the enzyme from Escherichia coli, which shows a higher specificity for ATP. A molecular explanation for the difference in the specificities of the two homologous enzymes is provided by the crystal structures of the complexes of the M. tuberculosis enzyme with (1) GMPPCP and pantothenate, (2) GDP and phosphopantothenate, (3) GDP, (4) GDP and pantothenate, (5) AMPPCP, and (6) GMPPCP, reported here, and the structures of the complexes of the two enzymes involving coenzyme A and different adenyl nucleotides reported earlier. The explanation is substantially based on two critical substitutions in the amino acid sequence and the local conformational change resulting from them. The structures also provide a rationale for the movement of ligands during the action of the mycobacterial enzyme. Dual specificity of the type exhibited by this enzyme is rare. The change in locations of ligands during action, observed in the case of the M. tuberculosis enzyme, is unusual, so is the striking difference between two homologous enzymes in the geometry of the binding site, locations of ligands, and specificity. Furthermore, the dual specificity of the mycobacterial enzyme appears to have been caused by a biological necessity.
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Affiliation(s)
- Bhaskar Chetnani
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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