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Huang SC, Chen CW, Satange R, Hsieh CC, Chang CC, Wang SC, Peng CL, Chen TL, Chiang MH, Horng YC, Hou MH. Targeting DNA junction sites by bis-intercalators induces topological changes with potent antitumor effects. Nucleic Acids Res 2024:gkae643. [PMID: 39036959 DOI: 10.1093/nar/gkae643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 06/21/2024] [Accepted: 07/09/2024] [Indexed: 07/23/2024] Open
Abstract
Targeting inter-duplex junctions in catenated DNA with bidirectional bis-intercalators is a potential strategy for enhancing anticancer effects. In this study, we used d(CGTATACG)2, which forms a tetraplex base-pair junction that resembles the DNA-DNA contact structure, as a model target for two alkyl-linked diaminoacridine bis-intercalators, DA4 and DA5. Cross-linking of the junction site by the bis-intercalators induced substantial structural changes in the DNA, transforming it from a B-form helical end-to-end junction to an over-wounded side-by-side inter-duplex conformation with A-DNA characteristics and curvature. These structural perturbations facilitated the angled intercalation of DA4 and DA5 with propeller geometry into two adjacent duplexes. The addition of a single carbon to the DA5 linker caused a bend that aligned its chromophores with CpG sites, enabling continuous stacking and specific water-mediated interactions at the inter-duplex contacts. Furthermore, we have shown that the different topological changes induced by DA4 and DA5 lead to the inhibition of topoisomerase 2 activities, which may account for their antitumor effects. Thus, this study lays the foundations for bis-intercalators targeting biologically relevant DNA-DNA contact structures for anticancer drug development.
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Affiliation(s)
- Shih-Chun Huang
- Doctoral Program in Medical Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Chia-Wei Chen
- Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan
| | - Roshan Satange
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | | | - Chih-Chun Chang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
| | - Shun-Ching Wang
- Doctoral Program in Medical Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Chi-Li Peng
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| | - Tai-Lin Chen
- Post Baccalaureate Medicine, School of Medicine, National Chung Hsing University, Taichung 402, Taiwan
| | - Ming-Hsi Chiang
- Institute of Chemistry, Academia Sinica, Taipei 11528, Taiwan
| | - Yih-Chern Horng
- Department of Chemistry, National Changhua University of Education, Changhua 50058, Taiwan
| | - Ming-Hon Hou
- Doctoral Program in Medical Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Graduate Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
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2
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Collins J, Osheroff N. Gyrase and Topoisomerase IV: Recycling Old Targets for New Antibacterials to Combat Fluoroquinolone Resistance. ACS Infect Dis 2024; 10:1097-1115. [PMID: 38564341 PMCID: PMC11019561 DOI: 10.1021/acsinfecdis.4c00128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/14/2024] [Accepted: 03/18/2024] [Indexed: 04/04/2024]
Abstract
Beyond their requisite functions in many critical DNA processes, the bacterial type II topoisomerases, gyrase and topoisomerase IV, are the targets of fluoroquinolone antibacterials. These drugs act by stabilizing gyrase/topoisomerase IV-generated DNA strand breaks and by robbing the cell of the catalytic activities of these essential enzymes. Since their clinical approval in the mid-1980s, fluoroquinolones have been used to treat a broad spectrum of infectious diseases and are listed among the five "highest priority" critically important antimicrobial classes by the World Health Organization. Unfortunately, the widespread use of fluoroquinolones has been accompanied by a rise in target-mediated resistance caused by specific mutations in gyrase and topoisomerase IV, which has curtailed the medical efficacy of this drug class. As a result, efforts are underway to identify novel antibacterials that target the bacterial type II topoisomerases. Several new classes of gyrase/topoisomerase IV-targeted antibacterials have emerged, including novel bacterial topoisomerase inhibitors, Mycobacterium tuberculosis gyrase inhibitors, triazaacenaphthylenes, spiropyrimidinetriones, and thiophenes. Phase III clinical trials that utilized two members of these classes, gepotidacin (triazaacenaphthylene) and zoliflodacin (spiropyrimidinetrione), have been completed with positive outcomes, underscoring the potential of these compounds to become the first new classes of antibacterials introduced into the clinic in decades. Because gyrase and topoisomerase IV are validated targets for established and emerging antibacterials, this review will describe the catalytic mechanism and cellular activities of the bacterial type II topoisomerases, their interactions with fluoroquinolones, the mechanism of target-mediated fluoroquinolone resistance, and the actions of novel antibacterials against wild-type and fluoroquinolone-resistant gyrase and topoisomerase IV.
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Affiliation(s)
- Jessica
A. Collins
- Department
of Biochemistry, Vanderbilt University School
of Medicine, Nashville, Tennessee 37232, United States
| | - Neil Osheroff
- Department
of Biochemistry, Vanderbilt University School
of Medicine, Nashville, Tennessee 37232, United States
- Department
of Medicine (Hematology/Oncology), Vanderbilt
University School of Medicine, Nashville, Tennessee 37232, United States
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3
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Faheem I, Gupta R, Nagaraja V. Distinct subunit architecture and assembly pattern of DNA gyrase from mycobacteria. Mol Microbiol 2023. [PMID: 37190861 DOI: 10.1111/mmi.15068] [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: 03/22/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 05/17/2023]
Abstract
DNA gyrase, the sole negative supercoiling type II topoisomerase, is composed of two subunits, GyrA and GyrB, encoded by the gyrA and gyrB genes, respectively, that form a quaternary complex of A2 B2 . In this study, we have investigated the assembly of mycobacterial DNA gyrase from its individual subunits, a step prerequisite for its activity. Using analytical size-exclusion chromatography, we show that GyrA from Mycobacterium tuberculosis and Mycobacterium smegmatis forms tetramers (A4 ) in solution unlike in Escherichia coli and other bacteria where GyrA exists as a dimer. GyrB, however, persists as a monomer, resembling the pattern found in E. coli. GyrB in both mycobacterial species interacts with GyrA and triggers the dissociation of the GyrA tetramer to facilitate the formation of catalytically active A2 B2 . Despite oligomerisation, the GyrA tetramer retained its DNA binding ability, and DNA binding had no effect on GyrA's oligomeric state in both species. Moreover, the presence of DNA facilitated the assembly of holoenzyme in the case of M. smegmatis by stabilising the GyrA2 B2 tetramer but with little effect in M. tuberculosis. Thus, in addition to the distinct organisation and regulation of the gyr locus in mycobacteria, the enzyme assembly also follows a different pattern.
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Affiliation(s)
- Iqball Faheem
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Richa Gupta
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
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4
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Galvin CJ, Hobson M, Meng JX, Ierokomos A, Ivanov IE, Berger JM, Bryant Z. Single-molecule dynamics of DNA gyrase in evolutionarily distant bacteria Mycobacterium tuberculosis and Escherichia coli. J Biol Chem 2023; 299:103003. [PMID: 36775125 PMCID: PMC10130225 DOI: 10.1016/j.jbc.2023.103003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
DNA gyrase is an essential nucleoprotein motor present in all bacteria and is a major target for antibiotic treatment of Mycobacterium tuberculosis (MTB) infection. Gyrase hydrolyzes ATP to add negative supercoils to DNA using a strand passage mechanism that has been investigated using biophysical and biochemical approaches. To analyze the dynamics of substeps leading to strand passage, single-molecule rotor bead tracking (RBT) has been used previously to follow real-time supercoiling and conformational transitions in Escherichia coli (EC) gyrase. However, RBT has not yet been applied to gyrase from other pathogenically relevant bacteria, and it is not known whether substeps are conserved across evolutionarily distant species. Here, we compare gyrase supercoiling dynamics between two evolutionarily distant bacterial species, MTB and EC. We used RBT to measure supercoiling rates, processivities, and the geometries and transition kinetics of conformational states of purified gyrase proteins in complex with DNA. Our results show that E. coli and MTB gyrases are both processive, with the MTB enzyme displaying velocities ∼5.5× slower than the EC enzyme. Compared with EC gyrase, MTB gyrase also more readily populates an intermediate state with DNA chirally wrapped around the enzyme, in both the presence and absence of ATP. Our substep measurements reveal common features in conformational states of EC and MTB gyrases interacting with DNA but also suggest differences in populations and transition rates that may reflect distinct cellular needs between these two species.
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Affiliation(s)
- Cooper J Galvin
- Program in Biophysics, Stanford University, Stanford, California, USA; Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Matthew Hobson
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Athena Ierokomos
- Program in Biophysics, Stanford University, Stanford, California, USA; Department of Bioengineering, Stanford University, Stanford, California, USA
| | - Ivan E Ivanov
- Department of Bioengineering, Stanford University, Stanford, California, USA; Department of Chemical Engineering, Stanford University, Stanford, California, USA
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zev Bryant
- Program in Biophysics, Stanford University, Stanford, California, USA; Department of Bioengineering, Stanford University, Stanford, California, USA; Department of Structural Biology, Stanford University Medical Center, Stanford, California, USA.
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5
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Hirsch J, Klostermeier D. What makes a type IIA topoisomerase a gyrase or a Topo IV? Nucleic Acids Res 2021; 49:6027-6042. [PMID: 33905522 PMCID: PMC8216471 DOI: 10.1093/nar/gkab270] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/26/2021] [Accepted: 04/01/2021] [Indexed: 12/14/2022] Open
Abstract
Type IIA topoisomerases catalyze a variety of different reactions: eukaryotic topoisomerase II relaxes DNA in an ATP-dependent reaction, whereas the bacterial representatives gyrase and topoisomerase IV (Topo IV) preferentially introduce negative supercoils into DNA (gyrase) or decatenate DNA (Topo IV). Gyrase and Topo IV perform separate, dedicated tasks during replication: gyrase removes positive supercoils in front, Topo IV removes pre-catenanes behind the replication fork. Despite their well-separated cellular functions, gyrase and Topo IV have an overlapping activity spectrum: gyrase is also able to catalyze DNA decatenation, although less efficiently than Topo IV. The balance between supercoiling and decatenation activities is different for gyrases from different organisms. Both enzymes consist of a conserved topoisomerase core and structurally divergent C-terminal domains (CTDs). Deletion of the entire CTD, mutation of a conserved motif and even by just a single point mutation within the CTD converts gyrase into a Topo IV-like enzyme, implicating the CTDs as the major determinant for function. Here, we summarize the structural and mechanistic features that make a type IIA topoisomerase a gyrase or a Topo IV, and discuss the implications for type IIA topoisomerase evolution.
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Affiliation(s)
- Jana Hirsch
- University of Muenster, Institute for Physical Chemistry, Corrensstrasse 30, 48149 Muenster, Germany
| | - Dagmar Klostermeier
- University of Muenster, Institute for Physical Chemistry, Corrensstrasse 30, 48149 Muenster, Germany
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6
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Stephanie F, Saragih M, Tambunan USF. Recent Progress and Challenges for Drug-Resistant Tuberculosis Treatment. Pharmaceutics 2021; 13:pharmaceutics13050592. [PMID: 33919204 PMCID: PMC8143172 DOI: 10.3390/pharmaceutics13050592] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/16/2021] [Accepted: 04/17/2021] [Indexed: 11/23/2022] Open
Abstract
Control of Mycobacterium tuberculosis infection continues to be an issue, particularly in countries with a high tuberculosis (TB) burden in the tropical and sub-tropical regions. The effort to reduce the catastrophic cost of TB with the WHO’s End TB Strategy in 2035 is still obstructed by the emergence of drug-resistant TB (DR-TB) cases as result of various mutations of the MTB strain. In the approach to combat DR-TB, several potential antitubercular agents were discovered as inhibitors for various existing and novel targets. Host-directed therapy and immunotherapy also gained attention as the drug-susceptibility level of the pathogen can be reduced due to the pathogen’s evolutionary dynamics. This review is focused on the current progress and challenges in DR-TB treatment. We briefly summarized antitubercular compounds that are under development and trials for both DR-TB drug candidates and host-directed therapy. We also highlighted several problems in DR-TB diagnosis, the treatment regimen, and drug discovery that have an impact on treatment adherence and treatment failure.
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7
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Rani P, Kalladi SM, Bansia H, Rao S, Jha RK, Jain P, Bhaduri T, Nagaraja V. A Type IA DNA/RNA Topoisomerase with RNA Hydrolysis Activity Participates in Ribosomal RNA Processing. J Mol Biol 2020; 432:5614-5631. [DOI: 10.1016/j.jmb.2020.08.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 01/19/2023]
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8
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Rani P, Nagaraja V. Genome-wide mapping of Topoisomerase I activity sites reveal its role in chromosome segregation. Nucleic Acids Res 2019; 47:1416-1427. [PMID: 30566665 PMCID: PMC6379724 DOI: 10.1093/nar/gky1271] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 11/30/2018] [Accepted: 12/13/2018] [Indexed: 11/13/2022] Open
Abstract
DNA Topoisomerase I (TopoI) in eubacteria is the principle DNA relaxase, belonging to Type 1A group. The enzyme from Mycobacterium smegmatis is essential for cell survival and distinct from other eubacteria in having several unusual characteristics. To understand genome-wide TopoI engagements in vivo, functional sites were mapped by employing a poisonous variant of the enzyme and a newly discovered inhibitor, both of which arrest the enzyme activity after the first transestrification reaction, thereby leading to the accumulation of protein-DNA covalent complexes. The cleavage sites are subsets of TopoI binding sites, implying that TopoI recruitment does not necessarily lead to DNA cleavage in vivo. The cleavage protection conferred by nucleoid associated proteins in vitro suggest a similar possibility in vivo. Co-localization of binding and cleavage sites of the enzyme on transcription units, implying that both TopoI recruitment and function are associated with active transcription. Attenuation of the cleavage upon Rifampicin treatment confirms the close connection between transcription and TopoI action. Notably, TopoI is inactive upstream of the Transcription start site (TSS) and activated following transcription initiation. The binding of TopoI at the Ter region, and the DNA cleavage at the Ter indicates TopoI involvement in chromosome segregation, substantiated by its catenation and decatenation activities.
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Affiliation(s)
- Phoolwanti Rani
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India
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9
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Szafran MJ, Strzałka A, Jakimowicz D. A highly processive actinobacterial topoisomerase I - thoughts on Streptomyces' demand for an enzyme with a unique C-terminal domain. MICROBIOLOGY-SGM 2019; 166:120-128. [PMID: 31390324 PMCID: PMC7398561 DOI: 10.1099/mic.0.000841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Topoisomerase I (TopA) is an essential enzyme that is required to remove excess negative supercoils from chromosomal DNA. Actinobacteria encode unusual TopA homologues with a unique C-terminal domain that contains lysine repeats and confers high enzyme processivity. Interestingly, the longest stretch of lysine repeats was identified in TopA from Streptomyces, environmental bacteria that undergo complex differentiation and produce a plethora of secondary metabolites. In this review, we aim to discuss potential advantages of the lysine repeats in Streptomyces TopA. We speculate that the chromosome organization, transcriptional regulation and lifestyle of these species demand a highly processive but also fine-tuneable relaxase. We hypothesize that the unique TopA provides flexible control of chromosomal topology and globally regulates gene expression.
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Affiliation(s)
- Marcin J Szafran
- Laboratory of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Agnieszka Strzałka
- Laboratory of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
| | - Dagmara Jakimowicz
- Laboratory of Molecular Microbiology, Faculty of Biotechnology, University of Wroclaw, Wroclaw, Poland
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10
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Datta C, Jha RK, Ahmed W, Ganguly S, Ghosh S, Nagaraja V. Physical and functional interaction between nucleoid-associated proteins HU and Lsr2 of Mycobacterium tuberculosis: altered DNA binding and gene regulation. Mol Microbiol 2019; 111:981-994. [PMID: 30633392 DOI: 10.1111/mmi.14202] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2019] [Indexed: 12/15/2022]
Abstract
Nucleoid-associated proteins (NAPs) in bacteria contribute to key activities such as DNA compaction, chromosome organization and regulation of gene expression. HU and Lsr2 are two principal NAPs in Mycobacterium tuberculosis (Mtb). HU is essential for Mtb survival and is one of the most abundant NAPs. It differs from other eubacterial HU proteins in having a long, flexible lysine- and arginine-rich carboxy-terminal domain. Lsr2 of Mtb is the functional analogue of the bacterial NAP commonly called H-NS. Lsr2 binds to and regulates expression of A/T-rich portions of the otherwise G/C-rich mycobacterial chromosome. Here, we demonstrate that HU and Lsr2 interact to form a complex. The interaction occurs primarily through the flexible carboxy-terminal domain of HU and the acidic amino-terminal domain of Lsr2. The resulting complex, upon binding to DNA, forms thick nucleoprotein rods, in contrast to the DNA bridging seen with Lsr2 and the DNA compaction seen with HU. Furthermore, transcription assays indicate that the HU-Lsr2 complex is a regulator of gene expression. This physical and functional interaction between two NAPs, which has not been reported previously, is likely to be important for DNA organization and gene expression in Mtb and perhaps other bacterial species.
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Affiliation(s)
- Chandreyee Datta
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Rajiv Kumar Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Sohini Ganguly
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Soumitra Ghosh
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, C.V. Raman Avenue, Bangalore, 560012, India.,Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, 560064, India
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11
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Chowdhury SR, Majumder HK. DNA Topoisomerases in Unicellular Pathogens: Structure, Function, and Druggability. Trends Biochem Sci 2019; 44:415-432. [PMID: 30609953 DOI: 10.1016/j.tibs.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/20/2018] [Accepted: 12/03/2018] [Indexed: 02/06/2023]
Abstract
All organisms, including unicellular pathogens, compulsorily possess DNA topoisomerases for successful nucleic acid metabolism. But particular subtypes of topoisomerases exist, in all prokaryotes and in some unicellular eukaryotes, that are absent in higher eukaryotes. Moreover, topoisomerases from pathogenic members of a niche possess some unique molecular architecture and functionalities completely distinct from their nonpathogenic colleagues. This review will highlight the unique attributes associated with the structures and functions of topoisomerases from the unicellular pathogens, with special reference to bacteria and protozoan parasites. It will also summarise the progress made in the domain pertaining to the druggability of these topoisomerases, upon which a future platform for therapeutic development can be successfully constructed.
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Affiliation(s)
- Somenath Roy Chowdhury
- Laboratory of Molecular Parasitology, Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700 032, India
| | - Hemanta K Majumder
- Laboratory of Molecular Parasitology, Infectious Diseases and Immunology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700 032, India.
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12
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Guha S, Udupa S, Ahmed W, Nagaraja V. Rewired Downregulation of DNA Gyrase Impacts Cell Division, Expression of Topology Modulators, and Transcription in Mycobacterium smegmatis. J Mol Biol 2018; 430:4986-5001. [PMID: 30316784 DOI: 10.1016/j.jmb.2018.10.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 09/22/2018] [Accepted: 10/02/2018] [Indexed: 10/28/2022]
Abstract
DNA gyrase, essential for DNA replication and transcription, has traditionally been studied in vivo by treatments that inhibit the enzyme activity. Due to its indispensable function, gyrA and gyrB deletions cannot be generated. The coumarin inhibitors of gyrase induce the supercoiling-sensitive gyrase promoter by a mechanism termed relaxation-stimulated transcription. Hence, to study the effect of sustained reduction in gyrase levels, a conditional-knockdown strain was generated in Mycobacterium smegmatis such that gyrase expression was controlled by a supercoiling non-responsive regulatory circuit. Decreasing intracellular gyrase protein levels beyond 50% affected cell growth. Reduced gyrase levels in the reprogrammed gyr operon caused chromosome relaxation, diffuse nucleoid structure, cell elongation, and altered gene expression. The key cell division protein, ftsZ, was severely reduced in the elongated cells, indicating a link between gyrase and cell division. Low levels of gyrase resulted in low compensatory expression of topoisomerase I and elevated expression of topology modulators hupB and lsr2. Altered supercoiling due to gyrase depletion caused corresponding changes in the RNA polymerase density on transcription units leading to their altered transcription. The enhanced susceptibility of the knockdown strain to anti-tubercular drugs suggests its utility for screening new molecules that may act synergistically with gyrase inhibitors.
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Affiliation(s)
- Sarmistha Guha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Shubha Udupa
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Valakunja Nagaraja
- 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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13
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García MT, Carreño D, Tirado-Vélez JM, Ferrándiz MJ, Rodrigues L, Gracia B, Amblar M, Ainsa JA, de la Campa AG. Boldine-Derived Alkaloids Inhibit the Activity of DNA Topoisomerase I and Growth of Mycobacterium tuberculosis. Front Microbiol 2018; 9:1659. [PMID: 30087665 PMCID: PMC6066988 DOI: 10.3389/fmicb.2018.01659] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/04/2018] [Indexed: 11/13/2022] Open
Abstract
The spread of multidrug-resistant isolates of Mycobacterium tuberculosis requires the discovery of new drugs directed to new targets. In this study, we investigated the activity of two boldine-derived alkaloids, seconeolitsine (SCN) and N-methyl-seconeolitsine (N-SCN), against M. tuberculosis. These compounds have been shown to target DNA topoisomerase I enzyme and inhibit growth of Streptococcus pneumoniae. Both SCN and N-SCN inhibited M. tuberculosis growth at 1.95-15.6 μM, depending on the strain. In M. smegmatis this inhibitory effect correlated with the amount of topoisomerase I in the cell, hence demonstrating that this enzyme is the target for these alkaloids in mycobacteria. The gene coding for topoisomerase I of strain H37Rv (MtbTopoI) was cloned into pQE1 plasmid of Escherichia coli. MtbTopoI was overexpressed with an N-terminal 6-His-tag and purified by affinity chromatography. In vitro inhibition of MtbTopoI activity by SCN and N-SCN was tested using a plasmid relaxation assay. Both SCN and N-SCN inhibited 50% of the enzymatic activity at 5.6 and 8.4 μM, respectively. Cleavage of single-stranded DNA was also inhibited with SCN. The effects on DNA supercoiling were also evaluated in vivo in plasmid-containing cultures of M. tuberculosis. Plasmid supercoiling densities were -0.060 in cells untreated or treated with boldine, and -0.072 in 1 × MIC N-SCN treated cells, respectively, indicating that the plasmid became hypernegatively supercoiled in the presence of N-SCN. Altogether, these results demonstrate that the M. tuberculosis topoisomerase I enzyme is an attractive drug target, and that SCN and N-SCN are promising lead compounds for drug development.
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Affiliation(s)
- María T. García
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - David Carreño
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - José M. Tirado-Vélez
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - María J. Ferrándiz
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Liliana Rodrigues
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Zaragoza, Zaragoza, Spain
- Fundación Agencia Aragonesa para la Investigación y el Desarrollo, Zaragoza, Spain
| | - Begoña Gracia
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Zaragoza, Zaragoza, Spain
| | - Mónica Amblar
- Unidad de Patología Molecular de Neumococo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - José A. Ainsa
- CIBER de Enfermedades Respiratorias, Madrid, Spain
- Departamento de Microbiología, Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad de Zaragoza, Zaragoza, Spain
| | - Adela G. de la Campa
- Unidad de Genética Bacteriana, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
- Presidencia, Consejo Superior de Investigaciones Científicas, Madrid, Spain
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14
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Ashley RE, Blower TR, Berger JM, Osheroff N. Recognition of DNA Supercoil Geometry by Mycobacterium tuberculosis Gyrase. Biochemistry 2017; 56:5440-5448. [PMID: 28921956 PMCID: PMC5637011 DOI: 10.1021/acs.biochem.7b00681] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
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Mycobacterium
tuberculosis encodes only a single
type II topoisomerase, gyrase. As a result, this enzyme likely carries
out the cellular functions normally performed by canonical gyrase
and topoisomerase IV, both in front of and behind the replication
fork. In addition, it is the sole target for quinolone antibacterials
in this species. Because quinolone-induced DNA strand breaks generated
on positively supercoiled DNA ahead of replication forks and transcription
complexes are most likely to result in permanent genomic damage, the
actions of M. tuberculosis gyrase on positively supercoiled
DNA were investigated. Results indicate that the enzyme acts rapidly
on overwound DNA and removes positive supercoils much faster than
it introduces negative supercoils into relaxed DNA. Canonical gyrase
and topoisomerase IV distinguish supercoil handedness differently
during the DNA cleavage reaction: while gyrase maintains lower levels
of cleavage complexes on overwound DNA, topoisomerase IV maintains
similar levels of cleavage complexes on both over- and underwound
substrates. M. tuberculosis gyrase maintained lower
levels of cleavage complexes on positively supercoiled DNA in the
absence and presence of quinolone-based drugs. By retaining this important
feature of canonical gyrase, the dual function M. tuberculosis type II enzyme remains a safe enzyme to act in front of replication
forks and transcription complexes. Finally, the N-terminal gate region
of the enzyme appears to be necessary to distinguish supercoil handedness
during DNA cleavage, suggesting that the capture of the transport
segment may influence how gyrase maintains cleavage complexes on substrates
with different topological states.
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Affiliation(s)
| | - Tim R Blower
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine , Baltimore, Maryland 21205-2185, United States
| | - James M Berger
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine , Baltimore, Maryland 21205-2185, United States
| | - Neil Osheroff
- VA Tennessee Valley Healthcare System , Nashville, Tennessee 37212, United States
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15
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Ahmed W, Sala C, Hegde SR, Jha RK, Cole ST, Nagaraja V. Transcription facilitated genome-wide recruitment of topoisomerase I and DNA gyrase. PLoS Genet 2017; 13:e1006754. [PMID: 28463980 PMCID: PMC5433769 DOI: 10.1371/journal.pgen.1006754] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 05/16/2017] [Accepted: 04/10/2017] [Indexed: 01/28/2023] Open
Abstract
Movement of the transcription machinery along a template alters DNA topology resulting in the accumulation of supercoils in DNA. The positive supercoils generated ahead of transcribing RNA polymerase (RNAP) and the negative supercoils accumulating behind impose severe topological constraints impeding transcription process. Previous studies have implied the role of topoisomerases in the removal of torsional stress and the maintenance of template topology but the in vivo interaction of functionally distinct topoisomerases with heterogeneous chromosomal territories is not deciphered. Moreover, how the transcription-induced supercoils influence the genome-wide recruitment of DNA topoisomerases remains to be explored in bacteria. Using ChIP-Seq, we show the genome-wide occupancy profile of both topoisomerase I and DNA gyrase in conjunction with RNAP in Mycobacterium tuberculosis taking advantage of minimal topoisomerase representation in the organism. The study unveils the first in vivo genome-wide interaction of both the topoisomerases with the genomic regions and establishes that transcription-induced supercoils govern their recruitment at genomic sites. Distribution profiles revealed co-localization of RNAP and the two topoisomerases on the active transcriptional units (TUs). At a given locus, topoisomerase I and DNA gyrase were localized behind and ahead of RNAP, respectively, correlating with the twin-supercoiled domains generated. The recruitment of topoisomerases was higher at the genomic loci with higher transcriptional activity and/or at regions under high torsional stress compared to silent genomic loci. Importantly, the occupancy of DNA gyrase, sole type II topoisomerase in Mtb, near the Ter domain of the Mtb chromosome validates its function as a decatenase. The generation of DNA topological constraint is intrinsic to transcription. Although in vitro studies indicated DNA gyrase and topoisomerase I action in the removal of excess supercoils, ahead and behind the transcribing RNA polymerase, in vivo recruitment and interaction of both topoisomerases with the genome has not been investigated. Using advanced sequencing, we have mapped the genome-wide footprints of topoisomerase I and DNA gyrase along with RNAP in deadly pathogen, Mycobacterium tuberculosis. We show that in vivo distribution of topoisomerases is guided by active transcription and both the enzymes co-occupy active transcription units. We establish their interaction with the regions of genome having propensity to accumulate negative and positive supercoiled domains, validating their role in managing the twin supercoiled domains.
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Affiliation(s)
- Wareed Ahmed
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Claudia Sala
- Ecole Polytechnique Federale de Lausanne, Global Health Institute, Station 19, Lausanne, Switzerland
| | - Shubhada R. Hegde
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Rajiv Kumar Jha
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Stewart T. Cole
- Ecole Polytechnique Federale de Lausanne, Global Health Institute, Station 19, Lausanne, Switzerland
- * E-mail: (VN); (STC)
| | - Valakunja Nagaraja
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- * E-mail: (VN); (STC)
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16
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DNA topoisomerase I and DNA gyrase as targets for TB therapy. Drug Discov Today 2017; 22:510-518. [DOI: 10.1016/j.drudis.2016.11.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/01/2016] [Accepted: 11/03/2016] [Indexed: 11/20/2022]
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17
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Ghosh S, Mallick B, Nagaraja V. Direct regulation of topoisomerase activity by a nucleoid-associated protein. Nucleic Acids Res 2014; 42:11156-65. [PMID: 25200077 PMCID: PMC4176182 DOI: 10.1093/nar/gku804] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The topological homeostasis of bacterial chromosomes is maintained by the balance between compaction and the topological organization of genomes. Two classes of proteins play major roles in chromosome organization: the nucleoid-associated proteins (NAPs) and topoisomerases. The NAPs bind DNA to compact the chromosome, whereas topoisomerases catalytically remove or introduce supercoils into the genome. We demonstrate that HU, a major NAP of Mycobacterium tuberculosis specifically stimulates the DNA relaxation ability of mycobacterial topoisomerase I (TopoI) at lower concentrations but interferes at higher concentrations. A direct physical interaction between M. tuberculosis HU (MtHU) and TopoI is necessary for enhancing enzyme activity both in vitro and in vivo. The interaction is between the amino terminal domain of MtHU and the carboxyl terminal domain of TopoI. Binding of MtHU did not affect the two catalytic trans-esterification steps but enhanced the DNA strand passage, requisite for the completion of DNA relaxation, a new mechanism for the regulation of topoisomerase activity. An interaction-deficient mutant of MtHU was compromised in enhancing the strand passage activity. The species-specific physical and functional cooperation between MtHU and TopoI may be the key to achieve the DNA relaxation levels needed to maintain the optimal superhelical density of mycobacterial genomes.
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Affiliation(s)
- Soumitra Ghosh
- Department of Microbiology and Cell biology, Indian Institute of Science, Bangalore 560012, India
| | - Bratati Mallick
- Department of Microbiology and Cell biology, Indian Institute of Science, Bangalore 560012, India
| | - Valakunja Nagaraja
- 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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18
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Molecular basis for the differential quinolone susceptibility of mycobacterial DNA gyrase. Antimicrob Agents Chemother 2014; 58:2013-20. [PMID: 24419347 DOI: 10.1128/aac.01958-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
DNA gyrase is a type II topoisomerase that catalyzes the introduction of negative supercoils in the genomes of eubacteria. Fluoroquinolones (FQs), successful as drugs clinically, target the enzyme to trap the gyrase-DNA complex, leading to the accumulation of double-strand breaks in the genome. Mycobacteria are less susceptible to commonly used FQs. However, an 8-methoxy-substituted FQ, moxifloxacin (MFX), is a potent antimycobacterial, and a higher susceptibility of mycobacterial gyrase to MFX has been demonstrated. Although several models explain the mechanism of FQ action and gyrase-DNA-FQ interaction, the basis for the differential susceptibility of mycobacterial gyrase to various FQs is not understood. We have addressed the basis of the differential susceptibility of the gyrase and revisited the mode of action of FQs. We demonstrate that FQs bind both Escherichia coli and Mycobacterium tuberculosis gyrases in the absence of DNA and that the addition of DNA enhances the drug binding. The FQs bind primarily to the GyrA subunit of mycobacterial gyrase, while in E. coli holoenzyme is the target. The binding of MFX to GyrA of M. tuberculosis correlates with its effectiveness as a better inhibitor of the enzyme and its efficacy in cell killing.
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