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Singh D, Tripathi P, Sharma R, Grover S, Batra JK. Role of a substrate binding pocket in the amino terminal domain of Mycobacterium tuberculosis caseinolytic protease B (ClpB) in its function. J Biomol Struct Dyn 2024; 42:6189-6199. [PMID: 37418201 DOI: 10.1080/07391102.2023.2232032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 06/27/2023] [Indexed: 07/08/2023]
Abstract
Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis when infects the host encounters several stresses within the host, resulting in aggregation of its proteins. To resolve this problem Mtb uses chaperones to either repair the damage or degrade the aggregated proteins. Mtb caseinolytic protein B (ClpB) helps in the prevention of aggregation and also resolubilization of aggregated proteins in bacteria, which is important for the survival of Mtb in the host. To function optimally, ClpB associates with its co-partners DnaK, DnaJ, and GrpE. The role of N-terminal domain (NTD) of Mtb ClpB in its function is not well understood. In this context, we investigated the interaction of three substrate mimicking peptides with the NTD of Mtb ClpB in silico. A substrate binding pocket, within the NTD of ClpB comprising of residues L136, R137, E138, K142, R144, R148, V149, Y158, and Y162 forming an ɑ-helix was thus identified. The residues L136 and R137 of the ɑ-helix were found to be important for the interaction of DnaK to ClpB. Further, nine single alanine recombinant variants of the identified residues were generated. As compared to the wild-type Mtb ClpB all the Mtb ClpB variants generated in this study were found to have reduced ATPase and protein refolding activity indicating the importance of the substrate binding pocket in ClpB function. The study demonstrates that the NTD of Mtb ClpB is important for its substrate interaction activity, and the substrate binding pocket identified in this study plays a crucial role in this interaction.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Digvijay Singh
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | | | - Rahul Sharma
- Department of Molecular Medicine, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | - Sonam Grover
- Department of Molecular Medicine, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
| | - Janendra K Batra
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi, India
- ICMR-National Institute of Pathology, Safdarjung Hospital Complex, New Delhi, India
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2
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Singh D, Sharma R, Jamal S, Agarwal M, Grover S, Batra JK. Identification and characterization of repurposed small molecule inhibitors of Mycobacterium tuberculosis caseinolytic protease B (ClpB) as anti-mycobacterials. Int J Biol Macromol 2024; 264:130614. [PMID: 38447849 DOI: 10.1016/j.ijbiomac.2024.130614] [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: 12/14/2023] [Revised: 02/29/2024] [Accepted: 03/02/2024] [Indexed: 03/08/2024]
Abstract
Mycobacterium tuberculosis (Mtb) caseinolytic protease B (ClpB) is a chaperone possessing a unique ability to resolubilize the aggregated proteins in vivo. ClpB has been shown to be important for the survival of Mtb within the host. Thus, it appears to be a promising target to develop new therapeutic molecules against tuberculosis. In this study, we have screened FDA approved compounds in silico to identify inhibitors against Mtb ClpB. In our screen, several compounds interacted with ClpB. The top four compounds, namely framycetin, gentamicin, ribostamycin and tobramycin showing the highest binding energy were selected for further investigation. MD simulations and tryptophan-based quenching of ClpB-drug complexes established that the selected inhibitors stably interacted with the target protein. The inhibitor and protein complexes were found to be stabilized by hydrogen bonding, and hydrophobic interactions. Although, the compounds did not affect the ATPase activity of ClpB significantly, the protein resolubilization activity of ClpB was remarkably reduced in their presence. All four compounds potently inhibited the growth of Mtb H37Ra. The antimycobacterial activity of the compounds appears to be due the inhibition of functional ClpB oligomer formation, in turn affecting its chaperonic activity.
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Affiliation(s)
- Digvijay Singh
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India
| | - Rahul Sharma
- Department of Molecular Medicine, School of Interdisciplinary Sciences and Technology, Jamia Hamdard, New Delhi 110062, India
| | - Salma Jamal
- Department of Molecular Medicine, School of Interdisciplinary Sciences and Technology, Jamia Hamdard, New Delhi 110062, India
| | - Meetu Agarwal
- Department of Molecular Medicine, School of Interdisciplinary Sciences and Technology, Jamia Hamdard, New Delhi 110062, India
| | - Sonam Grover
- Department of Molecular Medicine, School of Interdisciplinary Sciences and Technology, Jamia Hamdard, New Delhi 110062, India
| | - Janendra K Batra
- Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India; ICMR-National Institute of Pathology, Safdarjung Hospital Campus, New Delhi 110029, India.
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3
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Baruzzo G, Serafini A, Finotello F, Sanavia T, Cioetto-Mazzabò L, Boldrin F, Lavezzo E, Barzon L, Toppo S, Provvedi R, Manganelli R, Di Camillo B. Role of the Extracytoplasmic Function Sigma Factor SigE in the Stringent Response of Mycobacterium tuberculosis. Microbiol Spectr 2023; 11:e0294422. [PMID: 36946740 PMCID: PMC10100808 DOI: 10.1128/spectrum.02944-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 02/15/2023] [Indexed: 03/23/2023] Open
Abstract
Bacteria respond to nutrient starvation implementing the stringent response, a stress signaling system resulting in metabolic remodeling leading to decreased growth rate and energy requirements. A well-characterized model of stringent response in Mycobacterium tuberculosis is the one induced by growth in low phosphate. The extracytoplasmic function (ECF) sigma factor SigE was previously suggested as having a key role in the activation of stringent response. In this study, we challenge this hypothesis by analyzing the temporal dynamics of the transcriptional response of a sigE mutant and its wild-type parental strain to low phosphate using RNA sequencing. We found that both strains responded to low phosphate with a typical stringent response trait, including the downregulation of genes encoding ribosomal proteins and RNA polymerase. We also observed transcriptional changes that support the occurring of an energetics imbalance, compensated by a reduced activity of the electron transport chain, decreased export of protons, and a remodeling of central metabolism. The most striking difference between the two strains was the induction in the sigE mutant of several stress-related genes, in particular, the genes encoding the ECF sigma factor SigH and the transcriptional regulator WhiB6. Since both proteins respond to redox unbalances, their induction suggests that the sigE mutant is not able to maintain redox homeostasis in response to the energetics imbalance induced by low phosphate. In conclusion, our data suggest that SigE is not directly involved in initiating stringent response but in protecting the cell from stress consequent to the low phosphate exposure and activation of stringent response. IMPORTANCE Mycobacterium tuberculosis can enter a dormant state enabling it to establish latent infections and to become tolerant to antibacterial drugs. Dormant bacteria's physiology and the mechanism(s) used by bacteria to enter dormancy during infection are still unknown due to the lack of reliable animal models. However, several in vitro models, mimicking conditions encountered during infection, can reproduce different aspects of dormancy (growth arrest, metabolic slowdown, drug tolerance). The stringent response, a stress response program enabling bacteria to cope with nutrient starvation, is one of them. In this study, we provide evidence suggesting that the sigma factor SigE is not directly involved in the activation of stringent response as previously hypothesized, but it is important to help the bacteria to handle the metabolic stress related to the adaptation to low phosphate and activation of stringent response, thus giving an important contribution to our understanding of the mechanism behind stringent response development.
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Affiliation(s)
- Giacomo Baruzzo
- Department of Information Engineering, University of Padova, Padua, Italy
| | - Agnese Serafini
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | | | - Tiziana Sanavia
- Department of Information Engineering, University of Padova, Padua, Italy
| | | | - Francesca Boldrin
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Enrico Lavezzo
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Luisa Barzon
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | - Stefano Toppo
- Department of Molecular Medicine, University of Padova, Padua, Italy
| | | | | | - Barbara Di Camillo
- Department of Information Engineering, University of Padova, Padua, Italy
- Department of Comparative Biomedicine and Food Science, University of Padova, Padua, Italy
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4
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Riven I, Mazal H, Iljina M, Haran G. Fast dynamics shape the function of the
AAA
+ machine
ClpB
: lessons from single‐molecule
FRET
spectroscopy. FEBS J 2022. [DOI: 10.1111/febs.16539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 05/04/2022] [Accepted: 05/30/2022] [Indexed: 12/01/2022]
Affiliation(s)
- Inbal Riven
- Department of Chemical and Biological Physics Weizmann Institute of Science Rehovot Israel
| | - Hisham Mazal
- Department of Chemical and Biological Physics Weizmann Institute of Science Rehovot Israel
| | - Marija Iljina
- Department of Chemical and Biological Physics Weizmann Institute of Science Rehovot Israel
| | - Gilad Haran
- Department of Chemical and Biological Physics Weizmann Institute of Science Rehovot Israel
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5
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Yan S, Zhen J, Li Y, Huang Y, Ai X, Li Y, Stojkoska A, Huang X, Ruan C, Li J, Fan L, Xie J. Mycobacterium Lrp/AsnC family transcriptional factor modulates the arginase pathway as both a sensor and a transcriptional repressor. J Genet Genomics 2021; 48:1020-1031. [PMID: 34696992 DOI: 10.1016/j.jgg.2021.06.018] [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: 10/19/2020] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 12/26/2022]
Abstract
L-Arginine is the precursor of nitric oxide (NO), a host immune effector against intracellular pathogens including Mycobacterium tuberculosis (M. tb). Pathogens including M. tb have evolved various strategies targeting arginine to block the production of NO for better survival and proliferation. However, L-arginine metabolism and regulation in Mycobacterium are poorly understood. Here, we report the identification of M. smegmatis MSMEG_1415 (homolog of M. tb Rv2324) as an arginine-responsive transcriptional factor regulating the arginase pathway. In the absence of L-arginine, MSMEG_1415 acts as a repressor to inhibit the transcription of the roc (for arginine, ornithine catabolism) gene cluster, thereby switching off the arginase pathway. Treatment with L-arginine relieves the transcriptional inhibition of MSMEG_1415 on the roc gene cluster to activate the arginase pathway. Moreover, the L-arginine-MSMEG_1415 complex activates the transcription of the roc gene cluster by recognizing and binding a 15-bp palindrome motif, thereby preventing the excess accumulation of L-arginine in M. smegmatis. Physiologically, MSMEG_1415 confers mycobacteria resistance to starvation and fluoroquinolones exposure, suggestive of its important role in M. smegmatis persistence. The results uncover a unique regulatory mechanism of arginine metabolism in mycobacteria and identify M. tb Rv2324 as an attractive candidate target for the design of drugs against tuberculosis.
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Affiliation(s)
- Shuangquan Yan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Junfeng Zhen
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yuzhu Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yu Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xuefeng Ai
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Yue Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Andrea Stojkoska
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Xue Huang
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Cao Ruan
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Jiang Li
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China
| | - Lin Fan
- Shanghai Clinic and Research Center of Tuberculosis, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai Key Laboratory of Tuberculosis, Shanghai 200433, China.
| | - Jianping Xie
- Institute of Modern Biopharmaceuticals, State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Ministry of Education Eco-Environment of the Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing 400715, China.
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6
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Katikaridis P, Bohl V, Mogk A. Resisting the Heat: Bacterial Disaggregases Rescue Cells From Devastating Protein Aggregation. Front Mol Biosci 2021; 8:681439. [PMID: 34017857 PMCID: PMC8129007 DOI: 10.3389/fmolb.2021.681439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/12/2021] [Indexed: 11/23/2022] Open
Abstract
Bacteria as unicellular organisms are most directly exposed to changes in environmental growth conditions like temperature increase. Severe heat stress causes massive protein misfolding and aggregation resulting in loss of essential proteins. To ensure survival and rapid growth resume during recovery periods bacteria are equipped with cellular disaggregases, which solubilize and reactivate aggregated proteins. These disaggregases are members of the Hsp100/AAA+ protein family, utilizing the energy derived from ATP hydrolysis to extract misfolded proteins from aggregates via a threading activity. Here, we describe the two best characterized bacterial Hsp100/AAA+ disaggregases, ClpB and ClpG, and compare their mechanisms and regulatory modes. The widespread ClpB disaggregase requires cooperation with an Hsp70 partner chaperone, which targets ClpB to protein aggregates. Furthermore, Hsp70 activates ClpB by shifting positions of regulatory ClpB M-domains from a repressed to a derepressed state. ClpB activity remains tightly controlled during the disaggregation process and high ClpB activity states are likely restricted to initial substrate engagement. The recently identified ClpG (ClpK) disaggregase functions autonomously and its activity is primarily controlled by substrate interaction. ClpG provides enhanced heat resistance to selected bacteria including pathogens by acting as a more powerful disaggregase. This disaggregase expansion reflects an adaption of bacteria to extreme temperatures experienced during thermal based sterilization procedures applied in food industry and medicine. Genes encoding for ClpG are transmissible by horizontal transfer, allowing for rapid spreading of extreme bacterial heat resistance and posing a threat to modern food production.
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Affiliation(s)
- Panagiotis Katikaridis
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Valentin Bohl
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Axel Mogk
- Center for Molecular Biology of the Heidelberg University and German Cancer Research Center, DKFZ-ZMBH Alliance, Heidelberg, Germany
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7
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Yin Y, Feng X, Yu H, Fay A, Kovach A, Glickman MS, Li H. Structural basis for aggregate dissolution and refolding by the Mycobacterium tuberculosis ClpB-DnaK bi-chaperone system. Cell Rep 2021; 35:109166. [PMID: 34038719 PMCID: PMC8209680 DOI: 10.1016/j.celrep.2021.109166] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 12/30/2020] [Accepted: 05/03/2021] [Indexed: 11/30/2022] Open
Abstract
The M. tuberculosis (Mtb) ClpB is a protein disaggregase that helps to rejuvenate the bacterial cell. DnaK is a protein foldase that can function alone, but it can also bind to the ClpB hexamer to physically couple protein disaggregation with protein refolding, although the molecular mechanism is not well understood. Here, we report the cryo-EM analysis of the Mtb ClpB-DnaK bi-chaperone in the presence of ATPγS and a protein substrate. We observe three ClpB conformations in the presence of DnaK, identify a conserved TGIP loop linking the oligonucleotide/oligosaccharide-binding domain and the nucleotide-binding domain that is important for ClpB function, derive the interface between the regulatory middle domain of the ClpB and the DnaK nucleotide-binding domain, and find that DnaK binding stabilizes, but does not bend or tilt, the ClpB middle domain. We propose a model for the synergistic actions of aggregate dissolution and refolding by the Mtb ClpB-DnaK bi-chaperone system. Yin et al. use cryo-EM to analyze the structure of the Mycobacterium tuberculosis ClpB-DnaK bi-chaperone system. They find that the Mtb ClpB middle domain does not bend or tilt when interacting with DnaK. They therefore propose that the Mtb DnaK facilitates protein folding following protein disaggregation by ClpB.
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Affiliation(s)
- Yanting Yin
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Xiang Feng
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Hongjun Yu
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | - Allison Fay
- Immunology Program, Sloan Kettering Institute, New York, NY, USA
| | - Amanda Kovach
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA
| | | | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, MI, USA.
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8
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Iljina M, Mazal H, Goloubinoff P, Riven I, Haran G. Entropic Inhibition: How the Activity of a AAA+ Machine Is Modulated by Its Substrate-Binding Domain. ACS Chem Biol 2021; 16:775-785. [PMID: 33739813 PMCID: PMC8056383 DOI: 10.1021/acschembio.1c00156] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
ClpB is a tightly regulated AAA+ disaggregation machine. Each ClpB molecule is composed of a flexibly attached N-terminal domain (NTD), an essential middle domain (MD) that activates the machine by tilting, and two nucleotide-binding domains. The NTD is not well-characterized structurally and is commonly considered to serve as a dispensable substrate-binding domain. Here, we use single-molecule FRET spectroscopy to directly monitor the real-time dynamics of ClpB's NTD and reveal its unexpected autoinhibitory function. We find that the NTD fluctuates on the microsecond time scale, and these dynamics result in steric hindrance that limits the conformational space of the MD to restrict its tilting. This leads to significantly inhibited ATPase and disaggregation activities of ClpB, an effect that is alleviated upon binding of a substrate protein or the cochaperone DnaK. This entropic inhibition mechanism, which is mediated by ultrafast motions of the NTD and is not dependent on any strong interactions, might be common in related ATP-dependent proteases and other multidomain proteins to ensure their fast and reversible activation.
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Affiliation(s)
- Marija Iljina
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Hisham Mazal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Pierre Goloubinoff
- Department of Plant Molecular Biology, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Inbal Riven
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 761001, Israel
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9
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Singh P, Khurana H, Yadav SP, Dhiman K, Singh P, Ashish, Singh R, Sharma D. Biochemical characterization of ClpB protein from Mycobacterium tuberculosis and identification of its small-molecule inhibitors. Int J Biol Macromol 2020; 165:375-387. [PMID: 32987071 DOI: 10.1016/j.ijbiomac.2020.09.131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/25/2020] [Accepted: 09/18/2020] [Indexed: 12/14/2022]
Abstract
Tuberculosis, caused by pathogenic M. tuberculosis, remains a global health concern among various infectious diseases. Studies show that ClpB, a major disaggregase, protects the pathogen from various stresses encountered in the host environment. In the present study we have performed a detailed biophysical characterization of M. tuberculosis ClpB followed by a high throughput screening to identify small molecule inhibitors. The sedimentation velocity studies reveal that ClpB oligomerization varies with its concentration and presence of nucleotides. Further, using high throughput malachite green-based screening assay, we identified potential novel inhibitors of ClpB ATPase activity. The enzyme kinetics revealed that the lead molecule inhibits ClpB activity in a competitive manner. These drugs were also able to inhibit ATPase activity associated with E. coli ClpB and yeast Hsp104. The identified drugs inhibited the growth of intracellular bacteria in macrophages. Small angle X-ray scattering based modeling shows that ATP, and not its non-hydrolyzable analogs induce large scale conformational rearrangements in ClpB. Remarkably, the identified small molecules inhibited these ATP inducible conformational changes, suggesting that nucleotide induced shape changes are crucial for ClpB activity. The study broadens our understanding of M. tuberculosis chaperone machinery and provides the basis for designing more potent inhibitors against ClpB chaperone.
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Affiliation(s)
- Prashant Singh
- Council of Scientific and Industrial Research-Institute of Microbial Technology, India
| | - Harleen Khurana
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, India
| | - Shiv Pratap Yadav
- Council of Scientific and Industrial Research-Institute of Microbial Technology, India
| | - Kanika Dhiman
- Council of Scientific and Industrial Research-Institute of Microbial Technology, India
| | - Padam Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, India
| | - Ashish
- Council of Scientific and Industrial Research-Institute of Microbial Technology, India
| | - Ramandeep Singh
- Tuberculosis Research Laboratory, Translational Health Science and Technology Institute, India
| | - Deepak Sharma
- Council of Scientific and Industrial Research-Institute of Microbial Technology, India.
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10
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Tripathi P, Singh LK, Kumari S, Hakiem OR, Batra JK. ClpB is an essential stress regulator of Mycobacterium tuberculosis and endows survival advantage to dormant bacilli. Int J Med Microbiol 2020; 310:151402. [PMID: 32014406 DOI: 10.1016/j.ijmm.2020.151402] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/03/2019] [Accepted: 01/20/2020] [Indexed: 12/13/2022] Open
Abstract
The ability to tolerate multiple host derived stresses, resist eradication and persist within the infected individuals is central to the pathogenicity of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Mycobacterial survival is contingent upon sensing environmental perturbations and initiating a fitting response to counter them. Therefore, understanding of molecular mechanisms underlying stress tolerance and sensing in Mtb is critical for devising strategies for TB control. Our study aims to delineate the role of ClpB, a heat shock protein of Hsp100 family, in the general stress response and persistence mechanisms of Mtb. We demonstrate that Mtb requires ClpB to survive under stressful conditions. Additionally, we show that ClpB is necessary for the bacteria to persist in latency-like conditions such as prolonged hypoxia and nutrient-starvation. The disruption of ClpB results in aberrant cellular morphology, impaired biofilm formation and reduced infectivity of Mtb ex vivo. Our study also reports an alternative role of ClpB as a chaperokine which elicits inflammatory response in host. We conclude that ClpB is essential for Mtb to survive within macrophages, and plays a crucial part in the maintenance of dormant Mtb bacilli in latent state. The absence of ClpB in human genome makes it an attractive choice as drug target for TB.
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Affiliation(s)
- Prajna Tripathi
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Lalit K Singh
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Sujata Kumari
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Owais R Hakiem
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Janendra K Batra
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India; Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India.
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