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Luo G, Ming T, Yang L, He L, Tao T, Wang Y. Modulators targeting protein-protein interactions in Mycobacterium tuberculosis. Microbiol Res 2024; 284:127675. [PMID: 38636239 DOI: 10.1016/j.micres.2024.127675] [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: 09/27/2023] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 04/20/2024]
Abstract
Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (M. tuberculosis), mainly transmitted through droplets to infect the lungs, and seriously affecting patients' health and quality of life. Clinically, anti-TB drugs often entail side effects and lack efficacy against resistant strains. Thus, the exploration and development of novel targeted anti-TB medications are imperative. Currently, protein-protein interactions (PPIs) offer novel avenues for anti-TB drug development, and the study of targeted modulators of PPIs in M. tuberculosis has become a prominent research focus. Furthermore, a comprehensive PPI network has been constructed using computational methods and bioinformatics tools. This network allows for a more in-depth analysis of the structural biology of PPIs and furnishes essential insights for the development of targeted small-molecule modulators. Furthermore, this article provides a detailed overview of the research progress and regulatory mechanisms of PPI modulators in M. tuberculosis, the causative agent of TB. Additionally, it summarizes potential targets for anti-TB drugs and discusses the prospects of existing PPI modulators.
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Affiliation(s)
- Guofeng Luo
- School of Medical and Life Sciences, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Tianqi Ming
- State Key Laboratory of Southwestern Chinese Medicine Resources, Department of Pharmacology, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Luchuan Yang
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Lei He
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Tao Tao
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China
| | - Yanmei Wang
- Institute of traditional Chinese medicine, Sichuan College of traditional Chinese Medicine (Sichuan Second Hospital of TCM), Chengdu 610031, China.
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2
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Subramaniyan S, Nagarajan H, Vetrivel U, Jeyaraman J. Multilayer precision-based screening of potential inhibitors targeting Mycobacterium tuberculosis acetate kinase using in silico approaches. Comput Biol Chem 2023; 107:107942. [PMID: 37673012 DOI: 10.1016/j.compbiolchem.2023.107942] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 08/20/2023] [Accepted: 08/22/2023] [Indexed: 09/08/2023]
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (MTB), remains a major threat to global health, with the emergence of multi-drug and extensively drug-resistant strains posing a serious challenge. Thereby, understanding the molecular basis of MTB virulence and disease pathogenesis is critical for developing effective therapeutic strategies. Targeting proteins involved in central metabolism has been recognized as a promising therapeutic approach to combat MTB. In this regard, the enzyme AckA of the acetate metabolic pathway which produces acetate from acetyl phosphate, is an important drug target for various pathogenic organisms. Therefore, this study aimed to identify potential AckA inhibitors through in silico methods, including molecular modeling, molecular dynamics simulation (MDS), and high-throughput virtual screening (HTVS) followed by ADMETox, MMGBSA, Density Functional Theory (DFT) calculations. HTVS of one million compounds from the ZINC database against AckA resulted in the top five hits (ZINC82048449, ZINC1219737510, ZINC1771921358, ZINC119699567, and ZINC1427100376) with better binding affinity and optimal binding free energy. MDS studies on complexes revealed that key residues, Asn195, Asp266, Phe267, Gly314, and Asn318 played a significant role in stable interactions of the top-ranked compounds to AckA. These outcomes provide insights into the optimal binding of the leads to inhibit the acetate pathway and aid in the rational design of novel therapeutic agents. Thus, the identified leads may act as promising compounds for targeting AckA and may serve as a potential therapeutic modality for treating TB. Our findings offer valuable insights into the inhibition of the acetate pathway, while also serving as a blueprint for rational drug design. The identified leads hold promise as compelling compounds for targeting AckA, thereby offering a potential therapeutic avenue for tackling TB. Thus, our study uncovers a pathway toward promising TB therapeutics by elucidating AckA inhibitors. By leveraging in silico methodologies, potent compounds that hold the potential to thwart AckA's role in MTB's acetate pathway have been unveiled. This breakthrough fosters optimism in the quest for novel and effective TB treatments, addressing a global health challenge with renewed vigor.
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Affiliation(s)
- Sneha Subramaniyan
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi 630 003, Tamil Nadu, India
| | - Hemavathy Nagarajan
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi 630 003, Tamil Nadu, India
| | - Umashankar Vetrivel
- Virology & Biotechnology/Bioinformatics Division, ICMR-National Institute for Research in Tuberculosis, Chennai, Tamil Nadu 600 031, India
| | - Jeyakanthan Jeyaraman
- Structural Biology and Bio-Computing Lab, Department of Bioinformatics, Science Block, Alagappa University, Karaikudi 630 003, Tamil Nadu, India.
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3
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McDowell JR, Bai G, Lasek-Nesselquist E, Eisele LE, Wu Y, Hurteau G, Johnson R, Bai Y, Chen Y, Chan J, McDonough KA. Mycobacterial phosphodiesterase Rv0805 is a virulence determinant and its cyclic nucleotide hydrolytic activity is required for propionate detoxification. Mol Microbiol 2023; 119:401-422. [PMID: 36760076 PMCID: PMC10315211 DOI: 10.1111/mmi.15030] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 01/15/2023] [Accepted: 01/21/2023] [Indexed: 02/11/2023]
Abstract
Cyclic AMP (cAMP) signaling is essential to Mycobacterium tuberculosis (Mtb) pathogenesis. However, the roles of phosphodiesterases (PDEs) Rv0805, and the recently identified Rv1339, in cAMP homeostasis and Mtb biology are unclear. We found that Rv0805 modulates Mtb growth within mice, macrophages and on host-associated carbon sources. Mycobacterium bovis BCG grown on a combination of propionate and glycerol as carbon sources showed high levels of cAMP and had a strict requirement for Rv0805 cNMP hydrolytic activity. Supplementation with vitamin B12 or spontaneous genetic mutations in the pta-ackA operon restored the growth of BCGΔRv0805 and eliminated propionate-associated cAMP increases. Surprisingly, reduction of total cAMP levels by ectopic expression of Rv1339 restored only 20% of growth, while Rv0805 complementation fully restored growth despite a smaller effect on total cAMP levels. Deletion of an Rv0805 localization domain also reduced BCG growth in the presence of propionate and glycerol. We propose that localized Rv0805 cAMP hydrolysis modulates activity of a specialized pathway associated with propionate metabolism, while Rv1339 has a broader role in cAMP homeostasis. Future studies will address the biological roles of Rv0805 and Rv1339, including their impacts on metabolism, cAMP signaling and Mtb pathogenesis.
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Affiliation(s)
- James R. McDowell
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany NY 12208
| | - Guangchun Bai
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Immunology and Microbial Disease, MC-151, Albany Medical College, Albany, NY 12208-3479
| | - Erica Lasek-Nesselquist
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany NY 12208
| | - Leslie E. Eisele
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
| | - Yan Wu
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
| | - Gregory Hurteau
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
| | - Richard Johnson
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany NY 12208
| | - Yinlan Bai
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany NY 12208
| | - Yong Chen
- Albert Einstein College of Medicine, Bronx, NY
| | - John Chan
- Albert Einstein College of Medicine, Bronx, NY
| | - Kathleen A. McDonough
- Wadsworth Center, New York State Department of Health, Albany, NY 12208
- Department of Biomedical Sciences, School of Public Health, University at Albany, SUNY, Albany NY 12208
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4
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Acetylation of Cyclic AMP Receptor Protein by Acetyl Phosphate Modulates Mycobacterial Virulence. Microbiol Spectr 2023; 11:e0400222. [PMID: 36700638 PMCID: PMC9927398 DOI: 10.1128/spectrum.04002-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The success of Mycobacterium tuberculosis (Mtb) as a pathogen is partly attributed to its ability to sense and respond to dynamic host microenvironments. The cyclic AMP (cAMP) receptor protein (CRP) is closely related to the pathogenicity of Mtb and plays an important role in this process. However, the molecular mechanisms guiding the autoregulation and downstream target genes of CRP while Mtb responds to its environment are not fully understood. Here, it is demonstrated that the acetylation of conserved lysine 193 (K193) within the C-terminal DNA-binding domain of CRP reduces its DNA-binding ability and inhibits transcriptional activity. The reversible acetylation status of CRP K193 was shown to significantly affect mycobacterial growth phenotype, alter the stress response, and regulate the expression of biologically relevant genes using a CRP K193 site-specific mutation. Notably, the acetylation level of K193 decreases under CRP-activating conditions, including the presence of cAMP, low pH, high temperature, and oxidative stress, suggesting that microenvironmental signals can directly regulate CRP K193 acetylation. Both cell- and murine-based infection assays confirmed that CRP K193 is critical to the regulation of Mtb virulence. Furthermore, the acetylation of CRP K193 was shown to be dependent on the intracellular metabolic intermediate acetyl phosphate (AcP), and deacetylation was mediated by NAD+-dependent deacetylases. These findings indicate that AcP-mediated acetylation of CRP K193 decreases CRP activity and negatively regulates the pathogenicity of Mtb. We believe that the underlying mechanisms of cross talk between transcription, posttranslational modifications, and metabolites are a common regulatory mechanism for pathogenic bacteria. IMPORTANCE Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, and the ability of Mtb to survive harsh host conditions has been the subject of intensive research. As a result, we explored the molecular mechanisms guiding downstream target genes of CRP when Mtb responds to its environment. Our study makes a contribution to the literature because we describe the role of acetylated K193 in regulating its binding affinity to target DNA and influencing the virulence of mycobacteria. We discovered that mycobacteria can regulate their pathogenicity through the reversible acetylation of CRP K193 and that this reversible acetylation is mediated by AcP and a NAD+-dependent deacetylase. The regulation of CRPMtb by posttranslational modifications, at the transcriptional level, and by metabolic intermediates contribute to a better understanding of its role in the survival and pathogenicity of mycobacteria.
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5
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Chauhan P, Datta I, Dhiman A, Shankar U, Kumar A, Vashist A, Sharma TK, Tyagi JS. DNA Aptamer Targets Mycobacterium tuberculosis DevR/DosR Response Regulator Function by Inhibiting Its Dimerization and DNA Binding Activity. ACS Infect Dis 2022; 8:2540-2551. [PMID: 36332135 DOI: 10.1021/acsinfecdis.2c00414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tuberculosis is recognized as one of the major public health threats worldwide. The DevR-DevS (DosR/DosS) two-component system is considered a novel drug target in Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis, owing to its central role in bacterial adaptation and long-term persistence. An increase in DevR levels and the decreased permeability of the mycobacterial cell wall during hypoxia-associated dormancy pose formidable challenges to the development of anti-DevR compounds. Using an in vitro evolution approach of Systematic Evolution of Ligands by EXponential enrichment (SELEX), we developed a panel of single-stranded DNA aptamers that interacted with Mtb DevR protein in solid-phase binding assays. The best-performing aptamer, APT-6, forms a G-quadruplex structure and inhibits DevR-dependent transcription in Mycobacterium smegmatis. Mechanistic studies indicate that APT-6 functions by inhibiting the dimerization and DNA binding activity of DevR protein. In silico studies reveal that APT-6 interacts majorly with C-terminal domain residues that participate in DNA binding and formation of active dimer species of DevR. To the best of our knowledge, this is the first report of a DNA aptamer that inhibits the function of a cytosolic bacterial response regulator. By inhibiting the dimerization of DevR, APT-6 targets an essential step in the DevR activation mechanism, and therefore, it has the potential to universally block the expression of DevR-regulated genes for intercepting dormancy pathways in mycobacteria. These findings also pave the way for exploring aptamer-based approaches to design and develop potent inhibitors against intracellular proteins of various bacterial pathogens of global concern.
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Affiliation(s)
- Priyanka Chauhan
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Ishara Datta
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Abhijeet Dhiman
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Uma Shankar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Amit Kumar
- Department of Biosciences and Biomedical Engineering, Indian Institute of Technology Indore, Simrol, Indore453552, India
| | - Atul Vashist
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
| | - Tarun Kumar Sharma
- Translational Health Science and Technology Institute (THSTI), Faridabad, Haryana121001, India
| | - Jaya Sivaswami Tyagi
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi110029, India
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6
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Geng R, Cheng L, Cao C, Liu Z, Liu D, Xiao Z, Wu X, Huang Z, Feng Q, Luo C, Chen Z, Zhang Z, Jiang C, Ren M, Yang A. Comprehensive Analysis Reveals the Genetic and Pathogenic Diversity of Ralstonia solanacearum Species Complex and Benefits Its Taxonomic Classification. Front Microbiol 2022; 13:854792. [PMID: 35602040 PMCID: PMC9121018 DOI: 10.3389/fmicb.2022.854792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/22/2022] [Indexed: 11/23/2022] Open
Abstract
Ralstonia solanacearum species complex (RSSC) is a diverse group of plant pathogens that attack a wide range of hosts and cause devastating losses worldwide. In this study, we conducted a comprehensive analysis of 131 RSSC strains to detect their genetic diversity, pathogenicity, and evolution dynamics. Average nucleotide identity analysis was performed to explore the genomic relatedness among these strains, and finally obtained an open pangenome with 32,961 gene families. To better understand the diverse evolution and pathogenicity, we also conducted a series of analyses of virulence factors (VFs) and horizontal gene transfer (HGT) in the pangenome and at the single genome level. The distribution of VFs and mobile genetic elements (MGEs) showed significant differences among different groups and strains, which were consistent with the new nomenclatures of the RSSC with three distinct species. Further functional analysis showed that most HGT events conferred from Burkholderiales and played a great role in shaping the genomic plasticity and genetic diversity of RSSC genomes. Our work provides insights into the genetic polymorphism, evolution dynamics, and pathogenetic variety of RSSC and provides strong supports for the new taxonomic classification, as well as abundant resources for studying host specificity and pathogen emergence.
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Affiliation(s)
- Ruimei Geng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Lirui Cheng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Changdai Cao
- Shandong Rizhao Tobacco Company Ltd., Rizhao, China
| | - Zhengwen Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Dan Liu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiliang Xiao
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Xiuming Wu
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenrui Huang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Quanfu Feng
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Chenggang Luo
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhiqiang Chen
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Zhenchen Zhang
- Key Laboratory of Crop Genetic Improvement, Engineering and Technology Research Center for Tobacco Breeding and Comprehensive Utilization of Guangdong, Crops Research Institute of Guangdong Academy of Agricultural Sciences, Guangzhou, China
| | - Caihong Jiang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
| | - Min Ren
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- *Correspondence: Min Ren,
| | - Aiguo Yang
- Key Laboratory for Tobacco Gene Resources, Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, China
- Aiguo Yang,
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7
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Novel benzoic thiazolidin-4-one derivatives targeting DevR/DosR dormancy regulator of Mycobacterium tuberculosis. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2021.132278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Singh KK, Athira PJ, Bhardwaj N, Singh DP, Watson U, Saini DK. Acetylation of Response Regulator Protein MtrA in M. tuberculosis Regulates Its Repressor Activity. Front Microbiol 2021; 11:516315. [PMID: 33519719 PMCID: PMC7843721 DOI: 10.3389/fmicb.2020.516315] [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: 11/30/2019] [Accepted: 12/17/2020] [Indexed: 11/13/2022] Open
Abstract
MtrA is an essential response regulator (RR) protein in M. tuberculosis, and its activity is modulated after phosphorylation from its sensor kinase MtrB. Interestingly, many regulatory effects of MtrA have been reported to be independent of its phosphorylation, thereby suggesting alternate mechanisms of regulation of the MtrAB two-component system in M. tuberculosis. Here, we show that RR MtrA undergoes non-enzymatic acetylation through acetyl phosphate, modulating its activities independent of its phosphorylation status. Acetylated MtrA shows increased phosphorylation and enhanced interaction with SK MtrB assessed by phosphotransfer assays and FRET analysis. We also observed that acetylated MtrA loses its DNA-binding ability on gene targets that are otherwise enhanced by phosphorylation. More interestingly, acetylation is the dominant post-translational modification, overriding the effect of phosphorylation. Evaluation of the impact of MtrA and its lysine mutant overexpression on the growth of H37Ra bacteria under different conditions along with the infection studies on alveolar epithelial cells further strengthens the importance of acetylated MtrA protein in regulating the growth of M. tuberculosis. Overall, we show that both acetylation and phosphorylation regulate the activities of RR MtrA on different target genomic regions. We propose here that, although phosphorylation-dependent binding of MtrA drives its repressor activity on oriC and rpf, acetylation of MtrA turns this off and facilitates division in mycobacteria. Our findings, thus, reveal a more complex regulatory role of RR proteins in which multiple post-translational modifications regulate the activities at the levels of interaction with SK and the target gene expression.
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Affiliation(s)
- Krishna Kumar Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - P J Athira
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Neerupma Bhardwaj
- Molecular Biophysics Unit, Indian Institute of Science, Bengaluru, India
| | - Devendra Pratap Singh
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Uchenna Watson
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India.,Department of Studies in Zoology, University of Mysore, Mysore, India
| | - Deepak Kumar Saini
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bengaluru, India
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Sousa EH, Carepo MS, Moura JJ. Nitrate-nitrite fate and oxygen sensing in dormant Mycobacterium tuberculosis: A bioinorganic approach highlighting the importance of transition metals. Coord Chem Rev 2020. [DOI: 10.1016/j.ccr.2020.213476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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10
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Phosphatase-defective DevS sensor kinase mutants permit constitutive expression of DevR-regulated dormancy genes in Mycobacterium tuberculosis. Biochem J 2020; 477:1669-1682. [PMID: 32309848 DOI: 10.1042/bcj20200113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/10/2020] [Accepted: 04/20/2020] [Indexed: 11/17/2022]
Abstract
The DevR-DevS/DosR-DosS two-component system of Mycobacterium tuberculosis, that comprises of DevS sensor kinase and DevR response regulator, is essential for bacterial adaptation to hypoxia by inducing dormancy regulon expression. The dominant phosphatase activity of DevS under aerobic conditions enables tight negative control, whereas its kinase function activates DevR under hypoxia to induce the dormancy regulon. A net balance in these opposing kinase and phosphatase activities of DevS calibrates the response output of DevR. To gain mechanistic insights into the kinase-phosphatase balance of DevS, we generated alanine substitution mutants of five residues located in DHp α1 helix of DevS, namely Phe-403, Gly-406, Leu-407, Gly-411 and His-415. For the first time, we have identified kinase positive phosphatase negative (K+P-) mutants in DevS by a single-site mutation in either Gly-406 or Leu-407. M. tuberculosis Gly-406A and Leu-407A mutant strains constitutively expressed the DevR regulon under aerobic conditions despite the presence of negative signal, oxygen. These mutant proteins exhibited ∼2-fold interaction defect with DevR. We conclude that Gly-406 and Leu-407 residues are individually essential for the phosphatase function of DevS. Our study provides new insights into the negative control mechanism of DevS by demonstrating the importance of an optimal interaction between DevR and DevS, and local changes associated with individual residues, Gly-406 and Leu-407, which mimic ligand-free DevS. These K+P- mutant strains are expected to facilitate the rapid aerobic screening of DevR antagonists in M. tuberculosis, thereby eliminating the requirement for hypoxic culture conditions.
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Abstract
Progress against tuberculosis (TB) requires faster-acting drugs. Mycobacterium tuberculosis (Mtb) is the leading cause of death by an infectious disease and its treatment is challenging and lengthy. Mtb is remarkably successful, in part, due to its ability to become dormant in response to host immune pressures. The DosRST two-component regulatory system is induced by hypoxia, nitric oxide and carbon monoxide and remodels Mtb physiology to promote nonreplicating persistence (NRP). NRP bacteria are thought to play a role in the long course of TB treatment. Therefore, inhibitors of DosRST-dependent adaptation may function to kill this reservoir of persisters and potentially shorten therapy. This review examines the function of DosRST, newly discovered compounds that inhibit DosRST signaling and considers future development of DosRST inhibitors as adjunct therapies.
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