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Jiang Q, Hu R, Liu F, Huang F, Zhang L, Zhang H. Characterization of a Novel Oxidative Stress Responsive Transcription Regulator in Mycobacterium bovis. Biomedicines 2024; 12:1872. [PMID: 39200336 PMCID: PMC11351531 DOI: 10.3390/biomedicines12081872] [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: 07/28/2024] [Accepted: 08/14/2024] [Indexed: 09/02/2024] Open
Abstract
The antioxidant defense is critical for the survival of intracellular pathogens such as Mycobacterium tuberculosis complex (MTBC) species, including Mycobacterium bovis, which are often exposed to an oxidative environment caused by reactive oxygen species (ROS) in hosts. However, the signaling pathway in mycobacteria for sensing and responding to oxidative stress remains largely unclear. In this study, we characterize a TetR-type transcription regulator BCG_3893c, designated AotM, as a novel redox sensor in Mycobacterium bovis that increases mycobacterial tolerance to oxidative stress. AotM is required for the growth of M. bovis in the presence of 1 mM hydrogen peroxide. Loss of the aotM gene leads to altered transcriptional profiles with 352 genes significantly up-regulated and 25 genes significantly down-regulated. AotM recognizes a 14-bp palindrome sequence motif and negatively regulates the expression of a FAD-dependent oxidoreductase encoded by bcg_3892c. Overexpression of BCG_3892c increases intracellular ROS production and reduces the growth of M. bovis. In summary, we propose that AotM enhances the mycobacterial resistance against oxidative stress probably by inhibiting intracellular ROS production. Our findings reveal a novel underlying regulatory mechanism behind mycobacterial oxidative stress adaptation.
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Affiliation(s)
- Qiang Jiang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Rong Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Feng Liu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Feng Huang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
| | - Lei Zhang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China
| | - Hua Zhang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China; (Q.J.)
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2
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Anjou C, Lotoux A, Morvan C, Martin-Verstraete I. From ubiquity to specificity: The diverse functions of bacterial thioredoxin systems. Environ Microbiol 2024; 26:e16668. [PMID: 38899743 DOI: 10.1111/1462-2920.16668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/24/2024] [Indexed: 06/21/2024]
Abstract
The thioredoxin (Trx) system, found universally, is responsible for the regeneration of reversibly oxidized protein thiols in living cells. This system is made up of a Trx and a Trx reductase, and it plays a central role in maintaining thiol-based redox homeostasis by reducing oxidized protein thiols, such as disulfide bonds in proteins. Some Trxs also possess a chaperone function that is independent of thiol-disulfide exchange, in addition to their thiol-disulfide reductase activity. These two activities of the Trx system are involved in numerous physiological processes in bacteria. This review describes the diverse physiological roles of the Trx system that have emerged throughout bacterial evolution. The Trx system is essential for responding to oxidative and nitrosative stress. Beyond this primary function, the Trx system also participates in redox regulation and signal transduction, and in controlling metabolism, motility, biofilm formation, and virulence. This range of functions has evolved alongside the diversity of bacterial lifestyles and their specific constraints. This evolution can be characterized by the multiplication of the systems and by the specialization of cofactors or targets to adapt to the constraints of atypical lifestyles, such as photosynthesis, insect endosymbiosis, or spore-forming bacteria.
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Affiliation(s)
- Cyril Anjou
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Aurélie Lotoux
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Claire Morvan
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
| | - Isabelle Martin-Verstraete
- Institut Pasteur, Université Paris Cité, UMR CNRS 6047, Laboratoire Pathogenèse des Bactéries Anaérobies, Paris, France
- Institut Universitaire de France, Paris, France
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3
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Alves de Lima e Silva A, Rio-Tinto A. Ebselen: A Promising Repurposing Drug to Treat Infections Caused by Multidrug-Resistant Microorganisms. Interdiscip Perspect Infect Dis 2024; 2024:9109041. [PMID: 38586592 PMCID: PMC10998725 DOI: 10.1155/2024/9109041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 02/28/2024] [Accepted: 03/02/2024] [Indexed: 04/09/2024] Open
Abstract
Bacterial multiresistance to drugs is a rapidly growing global phenomenon. New resistance mechanisms have been described in different bacterial pathogens, threatening the effective treatment of even common infectious diseases. The problem worsens in infections associated with biofilms because, in addition to the pathogen's multiresistance, the biofilm provides a barrier that prevents antimicrobial access. Several "non-antibiotic" drugs have antimicrobial activity, even though it is not their primary therapeutic purpose. However, due to the urgent need to develop effective antimicrobials to treat diseases caused by multidrug-resistant pathogens, there has been an increase in research into "non-antibiotic" drugs to offer an alternative therapy through the so-called drug repositioning or repurposing. The prospect of new uses for existing drugs has the advantage of reducing the time and effort required to develop new compounds. Moreover, many drugs are already well characterized regarding toxicity and pharmacokinetic/pharmacodynamic properties. Ebselen has shown promise for use as a repurposing drug for antimicrobial purposes. It is a synthetic organoselenium with anti-inflammatory, antioxidant, and cytoprotective activity. A very attractive factor for using ebselen is that, in addition to potent antimicrobial activity, its minimum inhibitory concentration is very low for microbial pathogens.
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Affiliation(s)
- Agostinho Alves de Lima e Silva
- Laboratory of Biology and Physiology of Microorganisms, Biomedical Institute, DMP, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro 20211-030, Brazil
| | - André Rio-Tinto
- Laboratory of Pathogenic Cocci and Microbiota, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-853, Brazil
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4
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Tanifuji R, Kimura Y. Enzymatic characterization of five thioredoxins and a thioredoxin reductase from Myxococcus xanthus. FEMS Microbiol Lett 2024; 371:fnae058. [PMID: 39038987 DOI: 10.1093/femsle/fnae058] [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: 03/28/2024] [Revised: 06/24/2024] [Accepted: 07/20/2024] [Indexed: 07/24/2024] Open
Abstract
Thioredoxin (Trx) is a disulfide-containing redox protein that functions as a disulfide oxidoreductase. Myxococcus xanthus contains five Trxs (Trx1-Trx5) and one Trx reductase (TrxR). Trxs typically have a CGPC active-site motif; however, M. xanthus Trxs have slightly different active-site sequences, with the exception of Trx4. The five Trxs of M. xanthus exhibited reduced activities against insulin, 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB), cystine, glutathione disulfide (GSSG), S-nitrosoglutathione (GSNO), and H2O2 in the presence of TrxR. Myxococcus xanthus adenylate kinase and serine/threonine phosphatase activities, which were increased by the addition of dithiothreitol, were activated by the addition of Trxs and TrxR. Among these, Trx1, which has a CAPC sequence in its active site, exhibited the highest reducing activity with the exception of GSNO. Myxococcus xanthus TrxR showed weak reducing activity towards DTNB, GSSG, GSNO, and H2O2, suggesting that it has broad substrate specificity, unlike previously reported low-molecular-weight TrxRs. TrxR reduced oxidized Trx1 as the best substrate, with a kcat/Km value of 0.253 min-1 µM-1, which was 10-28-fold higher than that of the other Trxs. These results suggest that all Trxs possess reducing activity and that Trx1 may be the most functional in M. xanthus because TrxR most efficiently reduces oxidized Trx1.
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Affiliation(s)
- Ryota Tanifuji
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
| | - Yoshio Kimura
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki-cho, Kagawa 761-0795, Japan
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Sugandhi S, Rajmane V, Taunk K, Jadhav S, Nema V, Rapole S, Mande SC. The role of thioredoxin proteins in Mycobacterium tuberculosis probed by proteome-wide target profiling. Biochem Biophys Rep 2023; 35:101512. [PMID: 37521372 PMCID: PMC10371808 DOI: 10.1016/j.bbrep.2023.101512] [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] [Received: 04/17/2023] [Revised: 06/27/2023] [Accepted: 07/06/2023] [Indexed: 08/01/2023] Open
Abstract
Mycobacterium tuberculosis encounters diverse microenvironments, including oxidative assault (ROS and RNS), when it attempts to establish itself within its human host. Therefore, redox sensory and regulation processes are assumed significant importance, as these are essential processes for M. tuberculosis to survive under these hostile conditions. M. tuberculosis contains thioredoxin system to maintain redox homeostasis, which establish a balance between the thiol/dithiol couple. Still very less is known about it. In the present study, we attempted to capture the targets of all the M. tuberculosis thioredoxin proteins (viz., TrxB and TrxC) and a thioredoxin-like protein, NrdH, under aerobic and hypoxic conditions by performing thioredoxin trapping chromatography followed by mass spectrometry. We found that TrxC captured the maximum number of targets in both the physiological conditions and most of the targets of TrxB and NrdH showing overlap with targets of TrxC, indicating that TrxC acts as main thioredoxin. Further the PANTHER classification system provides involvement of targets in various metabolic processes and Gene Ontology analysis suggests that glutamine biosynthetic process and Fe-S cluster biosynthesis are the most enriched processes in the target list of TrxC and TrxB respectively. Also, we suggest that the thioredoxin system might play an important role under hypoxia by targeting those proteins which are responsible to sense and maintain hypoxic conditions. Furthermore, our studies establish a link between TrxB and iron-sulfur cluster biogenesis in M. tuberculosis. Ultimately, these findings open a new direction to target the thioredoxin system for screening new anti-mycobacterial drug targets.
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Affiliation(s)
- Sapna Sugandhi
- National Centre for Cell Science, Savitribai Phule Pune University Campus, Pune, India
| | - Vyankatesh Rajmane
- National Centre for Cell Science, Savitribai Phule Pune University Campus, Pune, India
| | - Khushman Taunk
- National Centre for Cell Science, Savitribai Phule Pune University Campus, Pune, India
| | - Sushama Jadhav
- Division of Molecular Biology, ICMR-National AIDS Research Institute, Pune, India
| | - Vijay Nema
- Division of Molecular Biology, ICMR-National AIDS Research Institute, Pune, India
| | - Srikanth Rapole
- National Centre for Cell Science, Savitribai Phule Pune University Campus, Pune, India
| | - Shekhar C. Mande
- National Centre for Cell Science, Savitribai Phule Pune University Campus, Pune, India
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6
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Koner D, Nag N, Kalita P, Padhi AK, Tripathi T, Saha N. Functional expression, localization, and biochemical characterization of thioredoxin glutathione reductase from air-breathing magur catfish, Clarias magur. Int J Biol Macromol 2023; 230:123126. [PMID: 36603726 DOI: 10.1016/j.ijbiomac.2022.123126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/22/2022] [Accepted: 12/30/2022] [Indexed: 01/04/2023]
Abstract
The glutathione (GSH) and thioredoxin (Trx) systems regulate cellular redox homeostasis and maintain antioxidant defense in most eukaryotes. We earlier reported the absence of gene coding for the glutathione reductase (GR) enzyme of the GSH system in the facultative air-breathing catfish, Clarias magur. Here, we identified three thioredoxin reductase (TrxR) genes, one of which was later confirmed as a thioredoxin glutathione reductase (TGR). We then characterized the novel recombinant TGR enzyme of C. magur (CmTGR). The tissue-specific expression of the txnrd genes and the tissue-specific activity of the TrxR enzyme were analyzed. The recombinant CmTGR is a dimer of ~133 kDa. The protein showed TrxR activity with 5,5'-diothiobis (2-nitrobenzoic acid) reduction assay with a Km of 304.40 μM and GR activity with a Km of 58.91 μM. Phylogenetic analysis showed that the CmTGR was related to the TrxRs of fishes and distantly related to the TGRs of platyhelminth parasites. The structural analysis revealed the conserved glutaredoxin active site and FAD- and NADPH-binding sites. To our knowledge, this is the first report of the presence of a TGR in any fish. This unusual presence of TGR in C. magur is crucial as it helps maintain redox homeostasis under environmental stressors-induced oxidative stress.
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Affiliation(s)
- Debaprasad Koner
- Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India
| | - Niharika Nag
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Parismita Kalita
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India
| | - Aditya K Padhi
- Laboratory for Computational Biology & Biomolecular Design, School of Biochemical Engineering, Indian Institute of Technology (BHU), Varanasi 221005, Uttar Pradesh, India
| | - Timir Tripathi
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong 793022, India.
| | - Nirmalendu Saha
- Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022, India.
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Shi X, Li C, Cheng L, Ullah H, Sha S, Kang J, Ma X, Ma Y. Mycobacterium tuberculosis Rv1324 Protein Contributes to Mycobacterial Persistence and Causes Pathological Lung Injury in Mice by Inducing Ferroptosis. Microbiol Spectr 2023; 11:e0252622. [PMID: 36625672 PMCID: PMC9927160 DOI: 10.1128/spectrum.02526-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is the pathogenic agent of tuberculosis (TB). Intracellular survival plays a central role in the pathogenesis of Mtb, a process that depends on an array of virulence factors for Mtb to colonize and proliferate within a host. Reactive nitrogen and oxygen species (RNS and ROS) are among the most effective antimycobacterial molecules generated by the host during infection. However, Mtb has evolved a number of proteins and enzymes to detoxify ROS and RNS. Secretory protein Rv1324, as a possible thioredoxin, might also have oxidoreductase activity against ROS and RNS during Mtb infection, and it is a potential virulence factor of Mtb. In this study, we investigated the biochemical properties of Mtb Rv1324 and its role in mycobacterial survival and virulence. The results showed that the Rv1324 protein had antioxidant activity and increased the survival of M. smegmatis that was exposed to ROS and RNS. In addition, Rv1324 enhanced the colonization ability of M. smegmatis in the lungs of mice. Further, mice infected with M. smegmatis harboring Rv1324 exhibited pathological injury and inflammation in the lung, which was mediated by ferroptosis. In summary, this study advances our understanding of the mechanisms of mycobacterial survival and pathogenesis, and it reveals a novel target for TB treatment. IMPORTANCE The intracellular survival of M. tuberculosis (Mtb) plays a crucial role in its pathogenesis, which depends on various Mtb oxidoreductases that are resistant to reactive oxygen and nitrogen species (ROS and RNS) that are generated by the host during Mtb infection. Secretory protein Rv1324 is a potential virulence factor of Mtb and is a possible thioredoxin that has oxidoreductase activity against ROS and RNS during Mtb infection. We investigated the biochemical properties of Mtb Rv1324 and its role in mycobacterial survival and virulence. It was confirmed that the Rv1324 protein had antioxidant activity and an increased mycobacterial resistance to ROS and RNS. In addition, Rv1324 enhanced mycobacterial persistence and induced pathological injury and inflammation in the lungs of mice by activating ferroptosis. This study advances our understanding of the mechanisms of mycobacterial survival and pathogenesis, and it reveals a novel target for TB treatment.
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Affiliation(s)
- Xiaoxia Shi
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
- Department of Experimental Teaching Center of Public Health, Dalian Medical University, Dalian, China
| | - Chunyu Li
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
| | - Lin Cheng
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
| | - Hayan Ullah
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
| | - Shanshan Sha
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
| | - Jian Kang
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
| | - Xiaochi Ma
- College of Integrative Medicine, Dalian Medical University, Dalian, China
- Pharmaceutical Research Center, The Second Affiliated Hospital, Dalian Medical University, Dalian, China
| | - Yufang Ma
- Department of Biochemistry and Molecular Biology, Dalian Medical University, Dalian, China
- Department of Microbiology, Dalian Medical University, Dalian, China
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8
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Choudhary E, Sharma R, Pal P, Agarwal N. Deciphering the Proteomic Landscape of Mycobacterium tuberculosis in Response to Acid and Oxidative Stresses. ACS OMEGA 2022; 7:26749-26766. [PMID: 35936415 PMCID: PMC9352160 DOI: 10.1021/acsomega.2c03092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/05/2022] [Indexed: 06/15/2023]
Abstract
The fundamental to the pathogenicity of Mycobacterium tuberculosis (Mtb) is the modulation in the control mechanisms that play a role in sensing and counteracting the microbicidal milieu encompassing various cellular stresses inside the human host. To understand such changes, we measured the cellular proteome of Mtb subjected to different stresses using a quantitative proteomics approach. We identified defined sets of Mtb proteins that are modulated in response to acid and a sublethal dose of diamide and H2O2 treatments. Notably, proteins involved in metabolic, catalytic, and binding functions are primarily affected under these stresses. Moreover, our analysis led to the observations that during acidic stress Mtb enters into energy-saving mode simultaneously modulating the acid tolerance system, whereas under diamide and H2O2 stresses, there were prominent changes in the biosynthesis and homeostasis pathways, primarily modifying the resistance mechanism in diamide-treated bacteria while causing metabolic arrest in H2O2-treated bacilli. Overall, we delineated the adaptive mechanisms that Mtb may utilize under physiological stresses and possible overlap between the responses to these stress conditions. In addition to offering important protein signatures that can be exploited for future mechanistic studies, our study highlights the importance of proteomics in understanding complex adjustments made by the human pathogen during infection.
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Affiliation(s)
- Eira Choudhary
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Symbiosis
School of Biomedical Sciences, Symbiosis
International (Deemed University), Pune412115, Maharashtra, India
| | - Rishabh Sharma
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
| | - Pramila Pal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
- Jawaharlal
Nehru University, New
Mehrauli Road, New Delhi110067, India
| | - Nisheeth Agarwal
- Laboratory
of Mycobacterial Genetics, Translational
Health Science and Technology Institute, NCR Biotech Science Cluster, Faridabad121001, Haryana, India
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9
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Willemse D, Moodley C, Mehra S, Kaushal D. Transcriptional Response of Mycobacterium tuberculosis to Cigarette Smoke Condensate. Front Microbiol 2021; 12:744800. [PMID: 34721344 PMCID: PMC8554204 DOI: 10.3389/fmicb.2021.744800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
Smoking is known to be an added risk factor for tuberculosis (TB), with nearly a quarter of the TB cases attributed to cigarette smokers in the 22 countries with the highest TB burden. Many studies have indicated a link between risk of active TB and cigarette smoke. Smoking is also known to significantly decrease TB cure and treatment completion rate and increase mortality rates. Cigarette smoke contains thousands of volatile compounds including carcinogens, toxins, reactive solids, and oxidants in both particulate and gaseous phase. Yet, to date, limited studies have analyzed the impact of cigarette smoke components on Mycobacterium tuberculosis (Mtb), the causative agent of TB. Here we report the impact of cigarette smoke condensate (CSC) on survival, mutation frequency, and gene expression of Mtb in vitro. We show that exposure of virulent Mtb to cigarette smoke increases the mutation frequency of the pathogen and strongly induces the expression of the regulon controlled by SigH—a global transcriptional regulator of oxidative stress. SigH has previously been shown to be required for Mtb to respond to oxidative stress, survival, and granuloma formation in vivo. A high-SigH expression phenotype is known to be associated with greater virulence of Mtb. In patients with pulmonary TB who smoke, these changes may therefore play an important, yet unexplored, role in the treatment efficacy by potentially enhancing the virulence of tubercle bacilli.
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Affiliation(s)
- Danicke Willemse
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Chivonne Moodley
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States.,Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, LA, United States
| | - Smriti Mehra
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States.,Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, LA, United States
| | - Deepak Kaushal
- Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, United States
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10
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Perween N, Pekhale K, Haval G, Mittal S, Ghaskadbi S, Ghaskadbi SS. Cloning and characterization of Thioredoxin 1 from the Cnidarian Hydra. J Biochem 2021; 171:41-51. [PMID: 34523686 DOI: 10.1093/jb/mvab092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 08/11/2021] [Indexed: 11/14/2022] Open
Abstract
Thioredoxins, small disulphide-containing redox proteins, play an important role in the regulation of cellular thiol redox balance through their disulfide reductase activity. In this study, we have identified, cloned, purified and characterized thioredoxin 1 (HvTrx1) from the Cnidarian Hydra vulgaris Ind-Pune. Bioinformatics analysis revealed that HvTrx1 contains an evolutionarily conserved catalytic active site CGPC and shows a closer phylogenetic relationship with vertebrate Trx1. Optimum pH and temperature for enzyme activity of purified HvTrx1 was found to be pH 7.0 and 25 °C respectively. Enzyme activity decreased significantly at acidic or alkaline pH as well as at higher temperatures. HvTrx1 was found to be expressed ubiquitously in whole mount in situ hybridization. Treatment of Hydra with hydrogen peroxide (H2O2), a highly reactive oxidizing agent, led to a significant increase in gene expression and enzyme activity of Trx1. Further experiments using PX12, an inhibitor of Trx1, indicated that Trx1 plays an important role in regeneration in Hydra. Finally, by using growth assay in E. coli and wound healing assay in human colon cancer cells, we demonstrate that HvTrx1 is functionally active in both prokaryotic and eukaryotic heterologous systems.
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Affiliation(s)
- Nusrat Perween
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.,Department of Zoology, Abeda Inamdar Senior College, Pune 411001, India
| | - Komal Pekhale
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India
| | - Gauri Haval
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India.,Department of Zoology, Abasaheb Garware College, Pune 411004, India
| | - Smriti Mittal
- Department of Biotechnology, Savitribai Phule Pune University, Pune 411007, India
| | - Surendra Ghaskadbi
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune 411004, India
| | - Saroj S Ghaskadbi
- Department of Zoology, Savitribai Phule Pune University, Pune 411007, India
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11
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Lata S, Akif M. Structure-based identification of natural compound inhibitor against M. tuberculosis thioredoxin reductase: insight from molecular docking and dynamics simulation. J Biomol Struct Dyn 2021; 39:4480-4489. [PMID: 32567497 DOI: 10.1080/07391102.2020.1778530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 05/30/2020] [Indexed: 12/19/2022]
Abstract
Antioxidant systems of M. tuberculosis (Mtb) play an important role in providing resistance in the hostile environment of mononuclear phagocytes. Thioredoxin system is a known antioxidant system that consists of three copies of thioredoxins (Trxs) and a single copy of thioredoxin reductase (TrxR). TrxR has been validated as an essential gene known to be involved in the reduction of peroxides, dinitrobenzenes and hydroperoxides, and is crucial in maintaining the survival of Mtb in macrophages. Recently, it has been demonstrated to be a druggable target. In this study, molecular docking was applied to screen more than 20,000 natural compounds from the Traditional Chinese Medicine database. Theoretical calculation of ΔGbinding by the Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) methods indicated two top-hit compounds that bind with a high affinity to the allosteric site, consisting of a hinge region, of TrxR. Further, stability and binding analysis of both compounds were carried out with molecular dynamics simulation. An analysis of conformational variation by principal component analysis (PCA) and protein contact network (PCN) uncovered the conformational changes in the compound-bound forms of protein. The NADPH domain formed many new interactions with the FAD domain in the compound-bound form, signifying that the binding may render an effect on the protein structure and function. Our results suggest that these two compounds could potentially be used for structure-based lead inhibitors against TrxR. The inhibitor selected as lead compound will be used further as a scaffold to optimize as novel anti-tuberculosis therapeutic.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Surabhi Lata
- Laboratory of Structural Biology, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, Telangana, India
| | - Mohd Akif
- Laboratory of Structural Biology, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Gachibowli, Hyderabad, Telangana, India
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12
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Mavi PS, Singh S, Kumar A. Reductive Stress: New Insights in Physiology and Drug Tolerance of Mycobacterium. Antioxid Redox Signal 2020; 32:1348-1366. [PMID: 31621379 DOI: 10.1089/ars.2019.7867] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Significance:Mycobacterium tuberculosis (Mtb) encounters reductive stress during its infection cycle. Notably, host-generated protective responses, such as acidic pH inside phagosomes and lysosomes, exposure to glutathione in alveolar hypophase (i.e., a thin liquid lining consisting of surfactant and proteins in the alveolus), and hypoxic environments inside granulomas are associated with the accumulation of reduced cofactors, such as nicotinamide adenine dinucleotide (reduced form), nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide (reduced form), and nonprotein thiols (e.g., mycothiol), leading to reductive stress in Mtb cells. Dissipation of this reductive stress is important for survival of the bacterium. If reductive stress is not dissipated, it leads to generation of reactive oxygen species, which may be fatal for the cells. Recent Advances: This review focuses on mechanisms utilized by mycobacteria to sense and respond to reductive stress. Importantly, exposure of Mtb cells to reductive stress leads to growth inhibition, altered metabolism, modulation of virulence, and drug tolerance. Mtb is equipped with thiol buffering systems of mycothiol and ergothioneine to protect itself from various redox stresses. These systems are complemented by thioredoxin and thioredoxin reductase (TR) systems for maintaining cellular redox homeostasis. A diverse array of sensors is used by Mycobacterium for monitoring its intracellular redox status. Upon sensing reductive stress, Mtb uses a flexible and robust metabolic system for its dissipation. Branched electron transport chain allows Mycobacterium to function with different terminal electron acceptors and modulate proton motive force to fulfill energy requirements under diverse scenarios. Interestingly, Mtb utilizes variations in the tricarboxylic cycle and a number of dehydrogenases to dissipate reductive stress. Upon prolonged exposure to reductive stress, Mtb utilizes biosynthesis of storage and virulence lipids as a dissipative mechanism. Critical Issues: The mechanisms utilized by Mycobacterium for sensing and tackling reductive stress are not well characterized. Future Directions: The precise role of thiol buffering and TR systems in neutralizing reductive stress is not well defined. Genetic systems that respond to metabolic reductive stress and thiol reductive stress need to be mapped. Genetic screens could aid in identification of such systems. Given that management of reductive stress is critical for both actively replicating and persister mycobacteria, an improved understanding of the mechanisms used by mycobacteria for dissipation of reductive stress may lead to identification of vulnerable choke points that could be targeted for killing Mtb in vivo.
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Affiliation(s)
- Parminder Singh Mavi
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Shweta Singh
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India
| | - Ashwani Kumar
- Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
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13
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Riaz SM, Bjune GA, Wiker HG, Sviland L, Mustafa T. Mycobacterial antigens accumulation in foamy macrophages in murine pulmonary tuberculosis lesions: Association with necrosis and making of cavities. Scand J Immunol 2020; 91:e12866. [PMID: 31960452 DOI: 10.1111/sji.12866] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 12/06/2019] [Accepted: 01/16/2020] [Indexed: 12/16/2022]
Abstract
Understanding mechanisms of cavitation in tuberculosis (TB) is the missing link that could advance the field towards better control of the infection. Descriptions of human TB suggest that postprimary TB begins as lipid pneumonia of foamy macrophages that undergoes caseating necrosis and fragmentation to produce cavities. This study aimed to investigate the various mycobacterial antigens accumulating in foamy macrophages and their relation to tissue destruction and necrosis. Pulmonary tissues from mice with slowly progressive TB were studied for histopathology, acid-fast bacilli (AFB) and presence of mycobacterial antigens. Digital quantification using Aperio ImageScope was done. Until week 12 postinfection, mice were healthy, and lesions were small with scarce AFB and mycobacterial antigens. Colony-forming units (CFUs) increased exponentially. At week 16-33, mice were sick, macrophages attained foamy appearance with an increase in antigens (P < .05), 1.5 log increase in CFUs and an approximately onefold increase in AFB. At week 37-41, mice started dying with a shift in morphology towards necrosis. A >20-fold increase in mycobacterial antigens was observed with only less than one log increase in CFUs and sevenfold increase in AFB. Secreted antigens were significantly (P < .05) higher compared to cell-wall antigens throughout infection. Focal areas of necrosis were associated with an approximately 40-fold increase in antigen MPT46, functionally active thioredoxin, and a significant increase in all secreted antigens. In conclusion, mycobacterial antigens accumulate in the foamy macrophages in TB lesions during slowly progressive murine pulmonary TB. Secreted antigens and MPT46 correlated with necrosis, thereby implying that they might trigger the formation of cavities.
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Affiliation(s)
- Syeda Mariam Riaz
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway
| | - Gunnar Aksel Bjune
- Department of Community Medicine, Institute of Health and Society, The Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Harald G Wiker
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Lisbet Sviland
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.,Department of Pathology, Haukeland University Hospital, Bergen, Norway
| | - Tehmina Mustafa
- Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.,Department of Thoracic Medicine, Haukeland University Hospital, Bergen, Norway
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Gample SP, Agrawal S, Sarkar D. Evidence of nitrite acting as a stable and robust inducer of non-cultivability in Mycobacterium tuberculosis with physiological relevance. Sci Rep 2019; 9:9261. [PMID: 31239517 PMCID: PMC6593118 DOI: 10.1038/s41598-019-45652-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/30/2019] [Indexed: 11/21/2022] Open
Abstract
Tuberculosis (TB) is the ninth leading cause of death worldwide, ranking above human immunodeficiency virus. Latency is the major obstacle in the eradication of this disease. How the physiology of the pathogen changes in transition to the latent stage needs to be understood. The latent bacteria extracted from animal hosts exist in a nonculturable (NC) phase, whereas bacteria extracted from most in vitro models are culture-positive. In the present study, we observed that nitrite, up to a concentration of 5 mM, shows the growth of Mycobacterium tuberculosis (MTB) in liquid media, but this effect starts reversing at higher concentrations. At a concentration of 10 mM, nitrite induces rapid nonculturability of MTB at the aerobic stage. This noncultivable dormancy was confirmed by analyzing the characteristics of NC bacteria. Further differential gene expression analyses clearly supported the formation of a dormancy phenotype. This study will be helpful for the use of this bacillus as a dormancy model in future studies on TB latency.
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Affiliation(s)
- Suwarna P Gample
- CSIR-National Chemical Laboratory, Organic Chemistry Division, Pune, 411008, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Sonia Agrawal
- CSIR-National Chemical Laboratory, Organic Chemistry Division, Pune, 411008, Maharashtra, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Dhiman Sarkar
- CSIR-National Chemical Laboratory, Organic Chemistry Division, Pune, 411008, Maharashtra, India. .,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
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15
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Burns-Huang K, Mundhra S. Mycobacterium tuberculosis cysteine biosynthesis genes mec+-cysO-cysM confer resistance to clofazimine. Tuberculosis (Edinb) 2019; 115:63-66. [DOI: 10.1016/j.tube.2019.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/25/2019] [Accepted: 02/03/2019] [Indexed: 11/16/2022]
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16
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Bose M, Bhattacharyya S, Biswas R, Roychowdhury A, Bhattacharjee A, Ghosh AK, Das AK. Elucidation of the mechanism of disulfide exchange between staphylococcal thioredoxin2 and thioredoxin reductase2: A structural insight. Biochimie 2019; 160:1-13. [PMID: 30710560 DOI: 10.1016/j.biochi.2019.01.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2018] [Accepted: 01/28/2019] [Indexed: 11/20/2022]
Abstract
The redox homeostasis of cytoplasm is maintained by a series of disulfide exchange reactions mediated by proteins belonging to the thioredoxin superfamily. Thioredoxin and thioredoxin reductase, being the major members of the family, play a key role in oxidative stress response of Staphylococcus aureus. In this report, we have identified and characterised an active thioredoxin system of the mentioned pathogen. Crystal structure of thioredoxin2 (SaTrx2) in its reduced form reveals that it contains the conserved redox active WCXXC motif and a thioredoxin fold. Thioredoxin reductase2 (SaTR2) is a flavoprotein and consists of two Rossmann folds as the binding sites for FAD and NADPH. Crystal structure of the SaTR2 holoenzyme shows that the protein consists of two domains and the catalytic site comprises of an intramolecular disulfide bond formed between two sequentially distal cysteine residues. Biophysical and biochemical studies unveil that SaTrx2 and SaTR2 can physically interact in solution and in the course of sustaining the redox equilibrium, the latter reduces the former. Molecular docking has been performed to illustrate the interface formed between SaTrx2 and SaTR2 during the disulfide exchange reaction.
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Affiliation(s)
- Madhuparna Bose
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Sudipta Bhattacharyya
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Rupam Biswas
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Amlan Roychowdhury
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Atanu Bhattacharjee
- Department of Biotechnology and Bioinformatics, North-Eastern Hill University, Shillong, 793022, India
| | - Ananta Kumar Ghosh
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India
| | - Amit Kumar Das
- Department of Biotechnology, Indian Institute of Technology Kharagpur, Kharagpur, 721302, India.
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Solution NMR Studies of Mycobacterium tuberculosis Proteins for Antibiotic Target Discovery. Molecules 2017; 22:molecules22091447. [PMID: 28858250 PMCID: PMC6151718 DOI: 10.3390/molecules22091447] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/27/2017] [Indexed: 11/17/2022] Open
Abstract
Tuberculosis is an infectious disease caused by Mycobacteriumtuberculosis, which triggers severe pulmonary diseases. Recently, multidrug/extensively drug-resistant tuberculosis strains have emerged and continue to threaten global health. Because of the development of drug-resistant tuberculosis, there is an urgent need for novel antibiotics to treat these drug-resistant bacteria. In light of the clinical importance of M. tuberculosis, 2067 structures of M. tuberculsosis proteins have been determined. Among them, 52 structures have been solved and studied using solution nuclear magnetic resonance (NMR). The functional details based on structural analysis of M. tuberculosis using NMR can provide essential biochemical data for the development of novel antibiotic drugs. In this review, we introduce diverse structural and biochemical studies on M. tuberculosis proteins determined using NMR spectroscopy.
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18
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Wong CF, Shin J, Subramanian Manimekalai MS, Saw WG, Yin Z, Bhushan S, Kumar A, Ragunathan P, Grüber G. AhpC of the mycobacterial antioxidant defense system and its interaction with its reducing partner Thioredoxin-C. Sci Rep 2017; 7:5159. [PMID: 28698569 PMCID: PMC5505994 DOI: 10.1038/s41598-017-05354-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 06/22/2017] [Indexed: 11/09/2022] Open
Abstract
Despite the highly oxidative environment of the phagosomal lumen, the need for maintaining redox homeostasis is a critical aspect of mycobacterial biology. The pathogens are equipped with the sophisticated thioredoxin- (Trx) and peroxiredoxin system, including TrxC and the alkyl hydroperoxide reductase subunit C (AhpC), whereby TrxC is one of the reducing partners of AhpC. Here we visualize the redox modulated dodecamer ring formation of AhpC from Mycobacterium bovis (BCG strain; MbAhpC) using electron microscopy and present novel insights into the unique N-terminal epitope (40 residues) of mycobacterial AhpC. Truncations and amino acid substitutions of residues in the unique N-terminus of MbAhpC provide insights into their structural and enzymatic roles, and into the evolutionary divergence of mycobacterial AhpC versus that of other bacteria. These structural details shed light on the epitopes and residues of TrxC which contributes to its interaction with AhpC. Since human cells lack AhpC, the unique N-terminal epitope of mycobacterial AhpC as well as the MbAhpC-TrxC interface represent an ideal drug target.
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Affiliation(s)
- Chui Fann Wong
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Joon Shin
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | | | - Wuan Geok Saw
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Zhan Yin
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore, 636921, Republic of Singapore
| | - Shashi Bhushan
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore.,NTU Institute of Structural Biology, Nanyang Technological University, 59 Nanyang Drive, Singapore, 636921, Republic of Singapore
| | - Arvind Kumar
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Priya Ragunathan
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore
| | - Gerhard Grüber
- Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore, 637551, Republic of Singapore.
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19
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Mycobacterium tuberculosis Proteome Response to Antituberculosis Compounds Reveals Metabolic "Escape" Pathways That Prolong Bacterial Survival. Antimicrob Agents Chemother 2017; 61:AAC.00430-17. [PMID: 28416555 DOI: 10.1128/aac.00430-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 03/31/2017] [Indexed: 11/20/2022] Open
Abstract
Tuberculosis (TB) continues to be one of the most common bacterial infectious diseases and is the leading cause of death in many parts of the world. A major limitation of TB therapy is slow killing of the infecting organism, increasing the risk for the development of a tolerance phenotype and drug resistance. Studies indicate that Mycobacterium tuberculosis takes several days to be killed upon treatment with lethal concentrations of antibiotics both in vitro and in vivo To investigate how metabolic remodeling can enable transient bacterial survival during exposure to bactericidal concentrations of compounds, M. tuberculosis strain H37Rv was exposed to twice the MIC of isoniazid, rifampin, moxifloxacin, mefloquine, or bedaquiline for 24 h, 48 h, 4 days, and 6 days, and the bacterial proteomic response was analyzed using quantitative shotgun mass spectrometry. Numerous sets of de novo bacterial proteins were identified over the 6-day treatment. Network analysis and comparisons between the drug treatment groups revealed several shared sets of predominant proteins and enzymes simultaneously belonging to a number of diverse pathways. Overexpression of some of these proteins in the nonpathogenic Mycobacterium smegmatis extended bacterial survival upon exposure to bactericidal concentrations of antimicrobials, and inactivation of some proteins in M. tuberculosis prevented the pathogen from escaping the fast killing in vitro and in macrophages, as well. Our biology-driven approach identified promising bacterial metabolic pathways and enzymes that might be targeted by novel drugs to reduce the length of tuberculosis therapy.
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20
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Gurung AB, Das AK, Bhattacharjee A. Disruption of redox catalytic functions of peroxiredoxin-thioredoxin complex in Mycobacterium tuberculosis H37Rv using small interface binding molecules. Comput Biol Chem 2017; 67:69-83. [DOI: 10.1016/j.compbiolchem.2016.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 09/19/2016] [Accepted: 12/30/2016] [Indexed: 10/20/2022]
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21
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Immune recognition surface construction of Mycobacterium tuberculosis epitope-specific antibody responses in tuberculosis patients identified by peptide microarrays. Int J Infect Dis 2017; 56:155-166. [DOI: 10.1016/j.ijid.2017.01.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/14/2017] [Indexed: 11/17/2022] Open
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22
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Sweeney NL, Lipker L, Hanson AM, Bohl CJ, Engel KE, Kalous KS, Stemper ME, Sem DS, Schwan WR. Docking into Mycobacterium tuberculosis Thioredoxin Reductase Protein Yields Pyrazolone Lead Molecules for Methicillin-Resistant Staphylococcus aureus. Antibiotics (Basel) 2017; 6:antibiotics6010004. [PMID: 28134858 PMCID: PMC5372984 DOI: 10.3390/antibiotics6010004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/19/2017] [Accepted: 01/23/2017] [Indexed: 01/20/2023] Open
Abstract
The thioredoxin/thioredoxin reductase system (Trx/TrxR) is an attractive drug target because of its involvement in a number of important physiological processes, from DNA synthesis to regulating signal transduction. This study describes the finding of pyrazolone compounds that are active against Staphylococcus aureus. Initially, the project was focused on discovering small molecules that may have antibacterial properties targeting the Mycobacterium tuberculosis thioredoxin reductase. This led to the discovery of a pyrazolone scaffold-containing compound series that showed bactericidal capability against S. aureus strains, including drug-resistant clinical isolates. The findings support continued development of the pyrazolone compounds as potential anti-S. aureus antibiotics.
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Affiliation(s)
- Noreena L Sweeney
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, 12800 N Lake Shore Dr, Mequon, WI 53097, USA.
| | - Lauren Lipker
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
| | - Alicia M Hanson
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, 12800 N Lake Shore Dr, Mequon, WI 53097, USA.
| | - Chris J Bohl
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, 12800 N Lake Shore Dr, Mequon, WI 53097, USA.
| | - Katie E Engel
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
| | - Kelsey S Kalous
- Department of Biochemistry, Medical College of Wisconsin, Wauwatosa, WI 53226, USA.
| | - Mary E Stemper
- Marshfield Clinic Research Foundation, Marshfield, WI 54449, USA.
| | - Daniel S Sem
- Department of Pharmaceutical Sciences, Concordia University Wisconsin, 12800 N Lake Shore Dr, Mequon, WI 53097, USA.
| | - William R Schwan
- Department of Microbiology, University of Wisconsin-La Crosse, La Crosse, WI 54601, USA.
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Dixit SK, Hota DP, Rajan P, Mishra PKK, Goswami TK, Mahawar M. Salmonella Typhimurium methionine sulfoxide reductase A (MsrA) prefers TrxA in repairing methionine sulfoxide. Prep Biochem Biotechnol 2016; 47:137-142. [DOI: 10.1080/10826068.2016.1185733] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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24
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Padayachee L, Pillay CS. The thioredoxin system and not the Michaelis-Menten equation should be fitted to substrate saturation datasets from the thioredoxin insulin assay. Redox Rep 2016; 21:170-179. [PMID: 26102065 PMCID: PMC8900709 DOI: 10.1179/1351000215y.0000000024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023] Open
Abstract
INTRODUCTION The thioredoxin system, consisting of thioredoxin reductase, thioredoxin and NADPH, is present in most living organisms and reduces a large array of target protein disulfides. OBJECTIVE The insulin reduction assay is commonly used to characterise thioredoxin activity in vitro, but it is not clear whether substrate saturation datasets from this assay should be fitted and modeled with the Michaelis-Menten equation (thioredoxin enzyme model), or fitted to the thioredoxin system with insulin reduction described by mass-action kinetics (redox couple model). METHODS We utilized computational modeling and in vitro assays to determine which of these approaches yield consistent and accurate kinetic parameter sets for insulin reduction. RESULTS Using computational modeling, we found that fitting to the redox couple model, rather than to the thioredoxin enzyme model, resulted in consistent parameter sets over a range of thioredoxin reductase concentrations. Furthermore, we established that substrate saturation in this assay was due to the progressive redistribution of the thioredoxin moiety into its oxidised form. We then confirmed these results in vitro using the yeast thioredoxin system. DISCUSSION This study shows how consistent parameter sets for thioredoxin activity can be obtained regardless of the thioredoxin reductase concentration used in the insulin reduction assay, and validates computational systems biology modeling studies that have described the thioredoxin system with the redox couple modeling approach.
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Affiliation(s)
- Letrisha Padayachee
- School of Life Sciences, University of KwaZulu-Natal, Carbis Road Campus, Pietermaritzburg3201, South Africa
| | - Ché S. Pillay
- School of Life Sciences, University of KwaZulu-Natal, Carbis Road Campus, Pietermaritzburg3201, South Africa
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Narihiro T, Kanosue Y, Hiraishi A. Cultural, Transcriptomic, and Proteomic Analyses of Water-Stressed Cells of Actinobacterial Strains Isolated from Compost: Ecological Implications in the Fed-Batch Composting Process. Microbes Environ 2016; 31:127-36. [PMID: 27246805 PMCID: PMC4912147 DOI: 10.1264/jsme2.me15199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/26/2016] [Indexed: 11/12/2022] Open
Abstract
This study was undertaken to examine the effects of water activity (aw) on the viability of actinobacterial isolates from a fed-batch composting (FBC) process by comparing culturability and stainability with 5-cyano-2,3-ditoryl tetrazolium chloride (CTC). The FBC reactor as the source of these bacteria was operated with the daily loading of household biowaste for 70 d. During this period of composting, aw in the reactor decreased linearly with time and reached approximately 0.95 at the end of operation. The plate counts of aerobic chemoorganotrophic bacteria were 3.2-fold higher than CTC-positive (CTC+) counts on average at the fully acclimated stage (after 7 weeks of operation), in which Actinobacteria predominated, as shown by lipoquinone profiling and cultivation methods. When the actinobacterial isolates from the FBC process were grown under aw stress, no significant differences were observed in culturability among the cultures, whereas CTC stainability decreased with reductions in aw levels. A cDNA microarray-based transcriptomic analysis of a representative isolate showed that many of the genes involved in cellular metabolism and genetic information processing were down-regulated by aw stress. This result was fully supported by a proteomic analysis. The results of the present study suggest that, in low aw mature compost, the metabolic activity of the community with Actinobacteria predominating is temporarily reduced to a level that hardly reacts with CTC; however, these bacteria are easily recoverable by exposure to a high aw culture medium. This may be a plausible reason why acclimated FBC reactors in which Actinobacteria predominate yields higher plate counts than CTC+ counts.
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Affiliation(s)
- Takashi Narihiro
- Department of Ecological Engineering, Toyohashi University of Technology ToyohashiAichi 441–8580Japan
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)Tsukuba, Ibaraki 305–8566Japan
| | - Yuji Kanosue
- Department of Ecological Engineering, Toyohashi University of Technology ToyohashiAichi 441–8580Japan
| | - Akira Hiraishi
- Department of Ecological Engineering, Toyohashi University of Technology ToyohashiAichi 441–8580Japan
- Department of Environmental and Life Sciences, Toyohashi University of Technology ToyohashiAichi 441–8580Japan
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26
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Li H, Wei JC. Functional analysis of thioredoxin from the desert lichen-forming fungus, Endocarpon pusillum Hedwig, reveals its role in stress tolerance. Sci Rep 2016; 6:27184. [PMID: 27251605 PMCID: PMC4890037 DOI: 10.1038/srep27184] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 05/13/2016] [Indexed: 01/05/2023] Open
Abstract
Endocarpon pusillum is a lichen-forming fungus with an outstanding stress resistance property closely related to its antioxidant system. In this study, thioredoxin (Trx), one of the main components of antioxidant defense systems in E. pusillum (EpTrx), was characterized and analyzed both in transgenic yeasts and in vitro. Our analyses identified that the heterologous expression of EpTrx in the yeast Pichia pastoris significantly enhanced its resistance to osmotic and oxidative stresses. Assays in vitro showed EpTrx acted as a disulfide reductase as well as a molecular chaperone by assembling into various polymeric structures. Upon exposure to heat-shock stress, EpTrx exhibited weaker disulfide reductase activity but stronger chaperone activity, which coincided with the switching of the protein complexes from low molecular weight forms to high molecular weight complexes. Specifically, we found that Cys31 near but not at the active site was crucial in promoting the structural and functional transitions, most likely by accelerating the formation of intermolecular disulfide bond. Transgenic Saccharomyces cerevisiae harboring the native EpTrx exhibited stronger tolerance to oxidative, osmotic and high temperature stresses than the corresponding yeast strain containing the mutant EpTrx (C31S). Our results provide the first molecular evidence on how Trx influences stress response in lichen-forming fungi.
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Affiliation(s)
- Hui Li
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jiang-Chun Wei
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Draft Genome Sequence of Mycobacterium bovis Strain SP38, a Pathogenic Bacterium Isolated from a Bovine in Brazil. GENOME ANNOUNCEMENTS 2015; 3:3/3/e00511-15. [PMID: 25999553 PMCID: PMC4440967 DOI: 10.1128/genomea.00511-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report a draft genome sequence of Mycobacterium bovis strain SP38, isolated from the lungs of a cow in Brazil. The assembly of reads resulted in 36 contigs in a total of approximately 4.37 Mb. Comparison of M. bovis strains sequenced to date will aid in understanding bovine tuberculosis in Brazil.
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Prabhavathi M, Pathakumari B, Raja A. IFN-γ/TNF-α ratio in response to immuno proteomically identified human T-cell antigens of Mycobacterium tuberculosis - The most suitable surrogate biomarker for latent TB infection. J Infect 2015; 71:238-49. [PMID: 25936741 DOI: 10.1016/j.jinf.2015.04.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/23/2015] [Accepted: 04/23/2015] [Indexed: 10/23/2022]
Abstract
The enormous reservoir of latent TB infection (LTBI) poses a major hurdle for global TB control. The existing Tuberculin skin test (TST) and IFN-γ release assays (IGRAs) are found to be suboptimal for LTBI diagnosis. Previously we had taken an immunoproteomic approach and identified 10 protein fractions (contains 16 proteins), which are solely recognized by LTBI. In a cohort of 40 pulmonary TB patients (PTB) and 35 healthy household contacts (HHC), IFN-γ and TNF-α response were measured against 16 antigens by using 1:10 diluted whole blood assay. Among all the antigens, IFN-γ response to Rv2626c has shown positivity of 88.57% in HHC and 7.5% in PTB group. IFN-γ response to combination of Rv2626c + Rv3716c has demonstrated 100% positivity in HHC and 17.5% positivity in PTB respectively. Compared to individual cytokines (i.e. IFN-γ and TNF-α), ratio of IFN-γ/TNF-α has shown promising results for diagnosis of LTBI. IFN-γ/TNF-α ratio against Rv3716c and TrxC has exhibited a positivity of 94.29% in HHC and 5% in PTB group. Accession of Rv2626c and Rv3716c may improve the diagnostic performance of existing QFT-GIT. Independent of QFT-GIT assay, ratio of IFN-γ/TNF-α in response to either Rv3716c or TrxC may acts as suitable surrogate biomarker for LTBI.
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Affiliation(s)
- Maddineni Prabhavathi
- Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetpet, Chennai 600 031, Tamil Nadu, India.
| | - Balaji Pathakumari
- Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetpet, Chennai 600 031, Tamil Nadu, India.
| | - Alamelu Raja
- Department of Immunology, National Institute for Research in Tuberculosis (ICMR), No. 1, Mayor Sathyamoorthy Road, Chetpet, Chennai 600 031, Tamil Nadu, India.
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Auranofin exerts broad-spectrum bactericidal activities by targeting thiol-redox homeostasis. Proc Natl Acad Sci U S A 2015; 112:4453-8. [PMID: 25831516 PMCID: PMC4394260 DOI: 10.1073/pnas.1504022112] [Citation(s) in RCA: 215] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Infections caused by antibiotic-resistant bacteria are a rising public health threat and make the identification of new antibiotics a priority. From a cell-based screen for bactericidal compounds against Mycobacterium tuberculosis under nutrient-deprivation conditions we identified auranofin, an orally bioavailable FDA-approved antirheumatic drug, as having potent bactericidal activities against both replicating and nonreplicating M. tuberculosis. We also found that auranofin is active against other Gram-positive bacteria, including Bacillus subtilis and Enterococcus faecalis, and drug-sensitive and drug-resistant strains of Enterococcus faecium and Staphylococcus aureus. Our biochemical studies showed that auranofin inhibits the bacterial thioredoxin reductase, a protein essential in many Gram-positive bacteria for maintaining the thiol-redox balance and protecting against reactive oxidative species. Auranofin decreases the reducing capacity of target bacteria, thereby sensitizing them to oxidative stress. Finally, auranofin was efficacious in a murine model of methicillin-resistant S. aureus infection. These results suggest that the thioredoxin-mediated redox cascade of Gram-positive pathogens is a valid target for the development of antibacterial drugs, and that the existing clinical agent auranofin may be repurposed to aid in the treatment of several important antibiotic-resistant pathogens.
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Efler P, Kilstrup M, Johnsen S, Svensson B, Hägglund P. Two Lactococcus lactis thioredoxin paralogues play different roles in responses to arsenate and oxidative stress. MICROBIOLOGY-SGM 2015; 161:528-38. [PMID: 25564497 DOI: 10.1099/mic.0.000029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Thioredoxin (Trx) maintains intracellular thiol groups in a reduced state and is involved in a wide range of cellular processes, including ribonucleotide reduction, sulphur assimilation, oxidative stress responses and arsenate detoxification. The industrially important lactic acid bacterium Lactococcus lactis contains two Trxs. TrxA is similar to the well-characterized Trx homologue from Escherichia coli and contains the common WCGPC active site motif, while TrxD is atypical and contains an aspartate residue in the active site (WCGDC). To elucidate the physiological roles of the two Trx paralogues, deletion mutants ΔtrxA, ΔtrxD and ΔtrxAΔtrxD were constructed. In general, the ΔtrxAΔtrxD strain was significantly more sensitive than either of the ΔtrxA and ΔtrxD mutants. Upon exposure to oxidative stress, growth of the ΔtrxA strain was diminished while that of the ΔtrxD mutant was similar to the wild-type. The lack of TrxA also appears to impair methionine sulphoxide reduction. Both ΔtrxA and ΔtrxD strains displayed growth inhibition after treatment with sodium arsenate and tellurite as compared with the wild-type, suggesting partially overlapping functions of TrxA and TrxD. Overall the phenotype of the ΔtrxA mutant matches established functions of WCGPC-type Trx while TrxD appears to play a more restricted role in stress resistance of Lac. lactis.
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Affiliation(s)
- Petr Efler
- Enzyme and Protein Chemistry, Søltofts Plads Building 224, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Mogens Kilstrup
- Center for Systems Microbiology, Matematiktorvet Building 301, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Stig Johnsen
- Enzyme and Protein Chemistry, Søltofts Plads Building 224, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Birte Svensson
- Enzyme and Protein Chemistry, Søltofts Plads Building 224, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
| | - Per Hägglund
- Enzyme and Protein Chemistry, Søltofts Plads Building 224, Department of Systems Biology, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
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Baker JJ, Johnson BK, Abramovitch RB. Slow growth of Mycobacterium tuberculosis at acidic pH is regulated by phoPR and host-associated carbon sources. Mol Microbiol 2014; 94:56-69. [PMID: 24975990 DOI: 10.1111/mmi.12688] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2014] [Indexed: 01/07/2023]
Abstract
During pathogenesis, Mycobacterium tuberculosis (Mtb) colonizes environments, such as the macrophage or necrotic granuloma, that are acidic and rich in cholesterol and fatty acids. The goal of this study was to examine how acidic pH and available carbon sources interact to regulate Mtb physiology. Here we report that Mtb growth at acidic pH requires host-associated carbon sources that function at the intersection of glycolysis and the TCA cycle, such as pyruvate, acetate, oxaloacetate and cholesterol. In contrast, in other tested carbon sources, Mtb fully arrests its growth at acidic pH and establishes a state of non-replicating persistence. Growth-arrested Mtb is resuscitated by the addition of pyruvate suggesting that growth arrest is due to a pH-dependent checkpoint on metabolism. Additionally, we demonstrate that the phoPR two-component regulatory system is required to slow Mtb growth at acidic pH and functions to maintain redox homeostasis. Transcriptional profiling and functional metabolic studies demonstrate that signals from acidic pH and carbon source are integrated to remodel pathways associated with anaplerotic central metabolism, lipid anabolism and the regeneration of oxidized cofactors. Because phoPR is required for Mtb virulence in animals, we suggest that pH-driven adaptation may be critical to Mtb pathogenesis.
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Affiliation(s)
- Jacob J Baker
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI, 48824, USA
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Kirtania P, Bhattacharya B, Das Gupta SK. Mycobacteriophage L5Gp56, a novel member of the NrdH family of redoxins. FEMS Microbiol Lett 2014; 357:16-22. [PMID: 24913246 DOI: 10.1111/1574-6968.12502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 06/03/2014] [Accepted: 06/05/2014] [Indexed: 11/29/2022] Open
Abstract
Mycobacteriophage L5 gene 56 encodes a putative thioredoxin family protein. Phylogenetic analysis revealed that Gp56 and related proteins are distantly related to NrdH - a glutaredoxin homolog which has thioredoxin-like properties. To understand its function, the recombinant version of the protein was biochemically characterized. For the sake of comparison, a mycobacterial thioredoxin, TrxB, was included in the study. Results show that Gp56 can be reduced by dithiothreitol, but only at a higher concentration as compared with TrxB, indicating that the standard redox potential of Gp56 is lower than that of TrxB. The reduced protein can subsequently act as a reductant of protein disulfide bonds. Gp56 can be reduced by NADPH with the help of thioredoxin reductase (TrxR) but less efficiently as compared with TrxB. The abilities of Gp56 and TrxB to reduce Gp50, the L5-encoded ribonucleotide reductase, was examined. While both are capable of executing this function, the former needs more reducing equivalents in the process as compared with the latter. This study shows that L5Gp56 represents a new class of NrdH-like proteins that function optimally in a reducing environment.
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Sanjeeva SK, Korrapati S, Nair CB, Rao PVS, Pullela PK, Vijayalakshmi U, Siva R. Hydrophobic interactions in donor-disulphide-acceptor (DSSA) probes looking beyond fluorescence resonance energy transfer theory. J Fluoresc 2014; 24:1297-306. [PMID: 24912449 DOI: 10.1007/s10895-014-1414-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 05/27/2014] [Indexed: 11/30/2022]
Abstract
Donor-linker-acceptor (DSSA) is a concept in fluorescence chemistry with acceptor being a fluorescent compound (FRET) or quencher. The DSSA probes used to measure thiol levels in vitro and in vivo. The reduction potential of these dyes are in the range of -0.60 V, much lower than the best thiol reductant reported in literature, the DTT (-0.33 V). DSSA disulphide having an unusually low reduction potential compared to the typical thiol reductants is a puzzle. Secondly, DSSA probes have a cyclized rhodamine ring as acceptor which does not have any spectral overlap with fluorescein, but quenches its absorbance and fluorescence. To understand the structural features of DSSA probes, we have synthesized DSSANa and DSSAOr. The calculated reduction potential of these dyes suggest that DSSA probes have an alternate mechanism from the FRET based quenching, namely hydrophobic interaction or dye to dye quenching. The standard reduction potential change with increasing complexity and steric hindrance of the molecule is small, suggesting that ultra- low Eo' has no contribution from the disulphide linker and is based on structural interactions between fluorescein and cyclized rhodamine. Our results help to understand the DSSA probe quenching mechanism and provide ways to design fluorescent probes.
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Abstract
ABSTRACT
During infection,
Mycobacterium tuberculosis
is exposed to a diverse array of microenvironments in the human host, each with its own unique set of redox conditions. Imbalances in the redox environment of the bacillus or the host environment serve as stimuli, which could regulate virulence. The ability of
M. tuberculosis
to evade the host immune response and cause disease is largely owing to the capacity of the mycobacterium to sense changes in its environment, such as host-generated gases, carbon sources, and pathological conditions, and alter its metabolism and redox balance accordingly for survival. In this article we discuss the redox sensors that are, to date, known to be present in
M. tuberculosis
, such as the Dos dormancy regulon, WhiB family, anti-σ factors, and MosR, in addition to the strategies present in the bacillus to neutralize free radicals, such as superoxide dismutases, catalase-peroxidase, thioredoxins, and methionine sulfoxide reductases, among others.
M. tuberculosis
is peculiar in that it appears to have a hierarchy of redox buffers, namely, mycothiol and ergothioneine. We discuss the current knowledge of their biosynthesis, function, and regulation. Ergothioneine is still an enigma, although it appears to have distinct and overlapping functions with mycothiol, which enable it to protect against a wide range of toxic metabolites and free radicals generated by the host. Developing approaches to quantify the intracellular redox status of the mycobacterium will enable us to determine how the redox balance is altered in response to signals and environments that mimic those encountered in the host.
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Machová I, Snašel J, Zimmermann M, Laubitz D, Plocinski P, Oehlmann W, Singh M, Dostál J, Sauer U, Pichová I. Mycobacterium tuberculosis phosphoenolpyruvate carboxykinase is regulated by redox mechanisms and interaction with thioredoxin. J Biol Chem 2014; 289:13066-78. [PMID: 24659783 DOI: 10.1074/jbc.m113.536748] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Tuberculosis remains a major health concern worldwide. Eradication of its causative agent, the bacterial pathogen Mycobacterium tuberculosis, is particularly challenging due to a vast reservoir of latent carriers of the disease. Despite the misleading terminology of a so-called dormant state associated with latent infections, the bacteria have to maintain basic metabolic activities. Hypoxic conditions have been widely used as an in vitro system to study this dormancy. Such studies identified a rearrangement of central carbon metabolism to exploit fermentative processes caused by the lack of oxygen. Phosphoenolpyruvate carboxykinase (Pck; EC 4.1.1.32) is the enzyme at the center of these metabolic rearrangements. Although Pck is associated with gluconeogenesis under standard growth conditions, the enzyme can catalyze the reverse reaction, supporting anaplerosis of the tricarboxylic acid cycle, under conditions leading to slowed or stopped bacterial replication. To study the mechanisms that regulate the switch between two Pck functions, we systematically investigated factors influencing the gluconeogenic and anaplerotic reaction kinetics. We demonstrate that a reducing environment, as found under hypoxia-triggered non-replicating conditions, accelerates the reaction in the anaplerotic direction. Furthermore, we identified proteins that interact with Pck. The interaction between Pck and the reduced form of mycobacterial thioredoxin, gene expression of which is increased under hypoxic conditions, also increased the Pck anaplerotic activity. We thus propose that a reducing environment and the protein-protein interaction with thioredoxin in particular enable the Pck anaplerotic function under fermentative growth conditions.
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Affiliation(s)
- Iva Machová
- From the Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic
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Abstract
The thioredoxin (Trx) system, which is composed of NADPH, thioredoxin reductase (TrxR), and thioredoxin, is a key antioxidant system in defense against oxidative stress through its disulfide reductase activity regulating protein dithiol/disulfide balance. The Trx system provides the electrons to thiol-dependent peroxidases (peroxiredoxins) to remove reactive oxygen and nitrogen species with a fast reaction rate. Trx antioxidant functions are also shown by involvement in DNA and protein repair by reducing ribonucleotide reductase, methionine sulfoxide reductases, and regulating the activity of many redox-sensitive transcription factors. Moreover, Trx systems play critical roles in the immune response, virus infection, and cell death via interaction with thioredoxin-interacting protein. In mammalian cells, the cytosolic and mitochondrial Trx systems, in which TrxRs are high molecular weight selenoenzymes, together with the glutathione-glutaredoxin (Grx) system (NADPH, glutathione reductase, GSH, and Grx) control the cellular redox environment. Recently mammalian thioredoxin and glutathione systems have been found to be able to provide the electrons crossly and to serve as a backup system for each other. In contrast, bacteria TrxRs are low molecular weight enzymes with a structure and reaction mechanism distinct from mammalian TrxR. Many bacterial species possess specific thiol-dependent antioxidant systems, and the significance of the Trx system in the defense against oxidative stress is different. Particularly, the absence of a GSH-Grx system in some pathogenic bacteria such as Helicobacter pylori, Mycobacterium tuberculosis, and Staphylococcus aureus makes the bacterial Trx system essential for survival under oxidative stress. This provides an opportunity to kill these bacteria by targeting the TrxR-Trx system.
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Affiliation(s)
- Jun Lu
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
| | - Arne Holmgren
- Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
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Raimunda D, Long JE, Padilla-Benavides T, Sassetti CM, Argüello JM. Differential roles for the Co(2+) /Ni(2+) transporting ATPases, CtpD and CtpJ, in Mycobacterium tuberculosis virulence. Mol Microbiol 2013; 91:185-97. [PMID: 24255990 DOI: 10.1111/mmi.12454] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/04/2013] [Indexed: 11/29/2022]
Abstract
The genome of Mycobacterium tuberculosis encodes two paralogous P1 B 4 -ATPases, CtpD (Rv1469) and CtpJ (Rv3743). Both proteins showed ATPase activation by Co(2+) and Ni(2+) , and both appear to be required for metal efflux from the cell. However, using a combination of biochemical and genetic studies we found that these proteins play non-redundant roles in virulence and metal efflux. CtpJ expression is induced by Co(2+) and this protein possesses a relatively high turnover rate. A ctpJ deletion mutant accumulated Co(2+) , indicating that this ATPase controls cytoplasmic metal levels. In contrast, CtpD expression is induced by redox stressors and this protein displays a relatively low turnover rate. A ctpD mutant failed to accumulate metal, suggesting an alternative cellular function. ctpD is cotranscribed with two thioredoxin genes trxA (Rv1470), trxB (Rv1471), and an enoyl-coA hydratase (Rv1472), indicating a possible role for CtpD in the metallation of these redox-active proteins. Supporting this, in vitro metal binding assays showed that TrxA binds Co(2+) and Ni(2+) . Mutation of ctpD, but not ctpJ, reduced bacterial fitness in the mouse lung, suggesting that redox maintenance, but not Co(2+) accumulation, is important for growth in vivo.
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Affiliation(s)
- Daniel Raimunda
- Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
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38
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Cossu A, Sechi LA, Bandino E, Zanetti S, Rosu V. Expression profiling of Mycobacterium tuberculosis H37Rv and Mycobacterium smegmatis in acid-nitrosative multi-stress displays defined regulatory networks. Microb Pathog 2013; 65:89-96. [PMID: 24184341 DOI: 10.1016/j.micpath.2013.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 10/17/2013] [Accepted: 10/23/2013] [Indexed: 11/26/2022]
Abstract
Several studies regarding the transcriptome of Mycobacterium tuberculosis following the exposure to various in vitro simulated phagosomal stressors, have already tried to elucidate the bacterium behavior during the intracellular infection. An in vitro acid-nitrosative multi-stress was carried out for M. tuberculosis H37Rv and Mycobacterium smegmatis MC(2)155 in order to analyze by DNA-microarray the gene expression changes associated respectively to pathogenic and non-pathogenic mycobacterial species. During acid-nitrosative multi-stress both mycobacteria shift their transcriptome to allow the anaerobic respiratory state and energy pathways characteristic of starvation. M. tuberculosis counteracts the combined acid-nitrosative stress more efficiently than M. smegmatis as also shown by the up-regulation of glbN and hmp genes, that are specifically directed to NO detoxification. Moreover, the down-regulation of some virulence factors involved in phthiocerol dimycocerosates synthesis strengthens the hypothesis that these major virulence determinants may be attenuated by M. tuberculosis in the presence of reactive nitrogen species. In fact, it down-regulates other genes implicated in the synthesis of membrane structural lipids but in contrast to M. smegmatis, M. tuberculosis up-regulates many genes annotated for the synthesis of peptidoglycan. Results suggest a gene regulation of M. tuberculosis which reveals a distinctive expression pattern under stressful environment.
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Affiliation(s)
- Andrea Cossu
- Department of Food Science, Division of Food Microbiology, University of Massachusetts, Amherst, MA 01003, USA.
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39
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Hanschmann EM, Godoy JR, Berndt C, Hudemann C, Lillig CH. Thioredoxins, glutaredoxins, and peroxiredoxins--molecular mechanisms and health significance: from cofactors to antioxidants to redox signaling. Antioxid Redox Signal 2013; 19:1539-605. [PMID: 23397885 PMCID: PMC3797455 DOI: 10.1089/ars.2012.4599] [Citation(s) in RCA: 493] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 02/01/2013] [Accepted: 02/07/2013] [Indexed: 12/19/2022]
Abstract
Thioredoxins (Trxs), glutaredoxins (Grxs), and peroxiredoxins (Prxs) have been characterized as electron donors, guards of the intracellular redox state, and "antioxidants". Today, these redox catalysts are increasingly recognized for their specific role in redox signaling. The number of publications published on the functions of these proteins continues to increase exponentially. The field is experiencing an exciting transformation, from looking at a general redox homeostasis and the pathological oxidative stress model to realizing redox changes as a part of localized, rapid, specific, and reversible redox-regulated signaling events. This review summarizes the almost 50 years of research on these proteins, focusing primarily on data from vertebrates and mammals. The role of Trx fold proteins in redox signaling is discussed by looking at reaction mechanisms, reversible oxidative post-translational modifications of proteins, and characterized interaction partners. On the basis of this analysis, the specific regulatory functions are exemplified for the cellular processes of apoptosis, proliferation, and iron metabolism. The importance of Trxs, Grxs, and Prxs for human health is addressed in the second part of this review, that is, their potential impact and functions in different cell types, tissues, and various pathological conditions.
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Affiliation(s)
- Eva-Maria Hanschmann
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
| | - José Rodrigo Godoy
- Institute of Physiology, Pathophysiology and Biophysics, Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Carsten Berndt
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Duesseldorf, Germany
| | - Christoph Hudemann
- Institute of Laboratory Medicine, Molecular Diagnostics, Philipps University, Marburg, Germany
| | - Christopher Horst Lillig
- Institute for Medical Biochemistry and Molecular Biology, University Medicine, Ernst-Moritz Arndt University, Greifswald, Germany
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40
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Phulera S, Mande SC. The Crystal Structure of Mycobacterium tuberculosis NrdH at 0.87 Å Suggests a Possible Mode of Its Activity. Biochemistry 2013; 52:4056-65. [DOI: 10.1021/bi400191z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Swastik Phulera
- National Centre for Cell Science,
NCCS Complex, University of Pune Campus, Ganeshkhind, Pune 411007,
Maharashtra, India
| | - Shekhar C. Mande
- National Centre for Cell Science,
NCCS Complex, University of Pune Campus, Ganeshkhind, Pune 411007,
Maharashtra, India
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41
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Davey L, Ng CKW, Halperin SA, Lee SF. Functional analysis of paralogous thiol-disulfide oxidoreductases in Streptococcus gordonii. J Biol Chem 2013; 288:16416-16429. [PMID: 23615907 DOI: 10.1074/jbc.m113.464578] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Disulfide bonds are important for the stability of many extracellular proteins, including bacterial virulence factors. Formation of these bonds is catalyzed by thiol-disulfide oxidoreductases (TDORs). Little is known about their formation in Gram-positive bacteria, particularly among facultative anaerobic Firmicutes, such as streptococci. To investigate disulfide bond formation in Streptococcus gordonii, we identified five putative TDORs from the sequenced genome. Each of the putative TDOR genes was insertionally inactivated with an erythromycin resistance cassette, and the mutants were analyzed for autolysis, extracellular DNA release, biofilm formation, bacteriocin production, and genetic competence. This analysis revealed a single TDOR, SdbA, which exhibited a pleiotropic mutant phenotype. Using an in silico analysis approach, we identified the major autolysin AtlS as a natural substrate of SdbA and showed that SdbA is critical to the formation of a disulfide bond that is required for autolytic activity. Analysis by BLAST search revealed homologs to SdbA in other Gram-positive species. This study provides the first in vivo evidence of an oxidoreductase, SdbA, that affects multiple phenotypes in a Gram-positive bacterium. SdbA shows low sequence homology to previously identified oxidoreductases, suggesting that it may belong to a different class of enzymes. Our results demonstrate that SdbA is required for disulfide bond formation in S. gordonii and indicate that this enzyme may represent a novel type of oxidoreductase in Gram-positive bacteria.
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Affiliation(s)
- Lauren Davey
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Crystal K W Ng
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Scott A Halperin
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada
| | - Song F Lee
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia B3H 1X5, Canada; Canadian Center for Vaccinology, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Pediatrics, Faculty of Medicine, Dalhousie University and the Izaak Walton Killam Health Centre, Halifax, Nova Scotia B3K 6R8, Canada; Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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42
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Olson AL, Neumann TS, Cai S, Sem DS. Solution structures of Mycobacterium tuberculosis thioredoxin C and models of intact thioredoxin system suggest new approaches to inhibitor and drug design. Proteins 2013; 81:675-89. [PMID: 23229911 PMCID: PMC3620657 DOI: 10.1002/prot.24228] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 10/26/2012] [Accepted: 11/12/2012] [Indexed: 11/08/2022]
Abstract
Here, we report the NMR solution structures of Mycobacterium tuberculosis (M. tuberculosis) thioredoxin C in both oxidized and reduced states, with discussion of structural changes that occur in going between redox states. The NMR solution structure of the oxidized TrxC corresponds closely to that of the crystal structure, except in the C-terminal region. It appears that crystal packing effects have caused an artifactual shift in the α4 helix in the previously reported crystal structure, compared with the solution structure. On the basis of these TrxC structures, chemical shift mapping, a previously reported crystal structure of the M. tuberculosis thioredoxin reductase (not bound to a Trx) and structures for intermediates in the E. coli thioredoxin catalytic cycle, we have modeled the complete M. tuberculosis thioredoxin system for the various steps in the catalytic cycle. These structures and models reveal pockets at the TrxR/TrxC interface in various steps in the catalytic cycle, which can be targeted in the design of uncompetitive inhibitors as potential anti-mycobacterial agents, or as chemical genetic probes of function.
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Affiliation(s)
- Andrew L Olson
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, USA
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Van Laer K, Dziewulska AM, Fislage M, Wahni K, Hbeddou A, Collet JF, Versées W, Mateos LM, Tamu Dufe V, Messens J. NrdH-redoxin of Mycobacterium tuberculosis and Corynebacterium glutamicum dimerizes at high protein concentration and exclusively receives electrons from thioredoxin reductase. J Biol Chem 2013; 288:7942-7955. [PMID: 23362277 PMCID: PMC3597831 DOI: 10.1074/jbc.m112.392688] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2012] [Revised: 01/22/2013] [Indexed: 11/06/2022] Open
Abstract
NrdH-redoxins are small reductases with a high amino acid sequence similarity with glutaredoxins and mycoredoxins but with a thioredoxin-like activity. They function as the electron donor for class Ib ribonucleotide reductases, which convert ribonucleotides into deoxyribonucleotides. We solved the x-ray structure of oxidized NrdH-redoxin from Corynebacterium glutamicum (Cg) at 1.5 Å resolution. Based on this monomeric structure, we built a homology model of NrdH-redoxin from Mycobacterium tuberculosis (Mt). Both NrdH-redoxins have a typical thioredoxin fold with the active site CXXC motif located at the N terminus of the first α-helix. With size exclusion chromatography and small angle x-ray scattering, we show that Mt_NrdH-redoxin is a monomer in solution that has the tendency to form a non-swapped dimer at high protein concentration. Further, Cg_NrdH-redoxin and Mt_NrdH-redoxin catalytically reduce a disulfide with a specificity constant 1.9 × 10(6) and 5.6 × 10(6) M(-1) min(-1), respectively. They use a thiol-disulfide exchange mechanism with an N-terminal cysteine pKa lower than 6.5 for nucleophilic attack, whereas the pKa of the C-terminal cysteine is ~10. They exclusively receive electrons from thioredoxin reductase (TrxR) and not from mycothiol, the low molecular weight thiol of actinomycetes. This specificity is shown in the structural model of the complex between NrdH-redoxin and TrxR, where the two surface-exposed phenylalanines of TrxR perfectly fit into the conserved hydrophobic pocket of the NrdH-redoxin. Moreover, nrdh gene deletion and disruption experiments seem to indicate that NrdH-redoxin is essential in C. glutamicum.
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Affiliation(s)
- Koen Van Laer
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium
| | - Aleksandra M Dziewulska
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium
| | - Marcus Fislage
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Khadija Wahni
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium
| | - Abderahim Hbeddou
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium
| | - Jean-Francois Collet
- Brussels Center for Redox Biology, 1050 Brussels, Belgium; de Duve Institute, Université Catholique de Louvain, 1200 Brussels, Belgium; Welbio, 1200 Brussels, Belgium
| | - Wim Versées
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Luis M Mateos
- Department of Molecular Biology, Area of Microbiology, University of León, 24071 León, Spain
| | - Veronica Tamu Dufe
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium; Welbio, 1200 Brussels, Belgium
| | - Joris Messens
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium.
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Serata M, Iino T, Yasuda E, Sako T. Roles of thioredoxin and thioredoxin reductase in the resistance to oxidative stress in Lactobacillus casei. Microbiology (Reading) 2012; 158:953-962. [DOI: 10.1099/mic.0.053942-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Masaki Serata
- Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan
| | - Tohru Iino
- Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan
| | - Emi Yasuda
- Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan
| | - Tomoyuki Sako
- Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi, Tokyo 186-8650, Japan
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45
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Trivedi A, Singh N, Bhat SA, Gupta P, Kumar A. Redox biology of tuberculosis pathogenesis. Adv Microb Physiol 2012; 60:263-324. [PMID: 22633061 DOI: 10.1016/b978-0-12-398264-3.00004-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Mycobacterium tuberculosis (Mtb) is one of the most successful human pathogens. Mtb is persistently exposed to numerous oxidoreductive stresses during its pathogenic cycle of infection and transmission. The distinctive ability of Mtb, not only to survive the redox stress manifested by the host but also to use it for synchronizing the metabolic pathways and expression of virulence factors, is central to its success as a pathogen. This review describes the paradigmatic redox and hypoxia sensors employed by Mtb to continuously monitor variations in the intracellular redox state and the surrounding microenvironment. Two component proteins, namely, DosS and DosT, are employed by Mtb to sense changes in oxygen, nitric oxide, and carbon monoxide levels, while WhiB3 and anti-sigma factor RsrA are used to monitor changes in intracellular redox state. Using these and other unidentified redox sensors, Mtb orchestrates its metabolic pathways to survive in nutrient-deficient, acidic, oxidative, nitrosative, and hypoxic environments inside granulomas or infectious lesions. A number of these metabolic pathways are unique to mycobacteria and thus represent potential drug targets. In addition, Mtb employs versatile machinery of the mycothiol and thioredoxin systems to ensure a reductive intracellular environment for optimal functioning of its proteins even upon exposure to oxidative stress. Mtb also utilizes a battery of protective enzymes, such as superoxide dismutase (SOD), catalase (KatG), alkyl hydroperoxidase (AhpC), and peroxiredoxins, to neutralize the redox stress generated by the host immune system. This chapter reviews the current understanding of mechanisms employed by Mtb to sense and neutralize redox stress and their importance in TB pathogenesis and drug development.
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Abstract
Mycobacterium tuberculosis (Mtb) is a metabolically flexible pathogen
that has the extraordinary ability to sense and adapt to the continuously changing host
environment experienced during decades of persistent infection. Mtb is
continually exposed to endogenous reactive oxygen species (ROS) as part of normal aerobic
respiration, as well as exogenous ROS and reactive nitrogen species (RNS) generated by the
host immune system in response to infection. The magnitude of tuberculosis (TB) disease is
further amplified by exposure to xenobiotics from the environment such as cigarette smoke
and air pollution, causing disruption of the intracellular
prooxidant–antioxidant balance. Both oxidative and reductive stresses induce
redox cascades that alter Mtb signal transduction, DNA and RNA synthesis,
protein synthesis and antimycobacterial drug resistance. As reviewed in this article,
Mtb has evolved specific mechanisms to protect itself against
endogenously produced oxidants, as well as defend against host and environmental oxidants
and reductants found specifically within the microenvironments of the lung. Maintaining an
appropriate redox balance is critical to the clinical outcome because several
antimycobacterial prodrugs are only effective upon bioreductive activation. Proper
homeostasis of oxido-reductive systems is essential for Mtb survival,
persistence and subsequent reactivation. The progress and remaining deficiencies in
understanding Mtb redox homeostasis are also discussed.
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Hall G, Bradshaw TD, Laughton CA, Stevens MF, Emsley J. Structure of Mycobacterium tuberculosis thioredoxin in complex with quinol inhibitor PMX464. Protein Sci 2011; 20:210-5. [PMID: 20981751 DOI: 10.1002/pro.533] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Thioredoxin (Trx) plays a critical role in the regulation of cellular redox homeostasis. Many disease causing pathogens rely on the Trx redox system for survival in conditions of environmental stress. The Trx redox system has been implicated in the resistance of Mycobacterium tuberculosis (Mtb) to phagocytosis. Trx is able to reduce a variety of target substrates and reactive oxygen species (ROS) through the cyclization of its active site dithiol to the oxidized disulphide Cys37-Cys40. Here we report the crystal structure of the Mtb Trx C active site mutant C40S (MtbTrxCC40S) in isolation and in complex with the hydroxycyclohexadienone inhibitor PMX464. We observe PMX464 is covalently bound to the active site residue Cys37 through Michael addition of the cyclohexadienone ring and also forms noncovalent contacts which mimic the binding of natural Trx ligands. In comparison with the ligand free MtbTrxCC40S structure a conformational change occurs in the PMX464 complex involving movement of helix α2 and the active site loop. These changes are almost identical to those observed for helix α2 in human Trx ligand complexes. Whereas the ligand free structure forms a homodimer the inhibitor complex unexpectedly forms a different dimer with one PMX464 molecule bound at the interface. This 2:1 MtbTrxCC40S-PMX464 complex is also observed using mass spectrometry measurements. This structure provides an unexpected scaffold for the design of improved Trx inhibitors targeted at developing treatments for tuberculosis.
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Affiliation(s)
- Gareth Hall
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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Phylogenetic clustering of 4 prevalent virulence genes in Orientia tsutsugamushi isolates from human patients. J Microbiol 2010; 48:124-8. [PMID: 20221740 DOI: 10.1007/s12275-009-0267-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 10/26/2009] [Indexed: 10/19/2022]
Abstract
The pathogenicity of microbes is involved in many kinds of virulence genes. The relationships between these virulence genes and strains are not clear in Orientia tsutsugamushi yet. In this study, we confirmed the presence of the virulence genes and classified into O. tsutsugamushi isolates using phylogenetic analysis of the virulence genes. We also compared the fatality rates of every isolate via an infection experiment in BALB/c mice using the O. tsutsugamushi isolates, Deajeon03-01, Wonju03-01, and Muju03-01. Moreover, we compared the phylogenetic analysis, in basis with 56 kDa protein sequence which determined from serotype, and virulence genes of O. tsutsugamushi. Our results showed remarkably different fatality rates between Deajeon03-01 and Muju03-01, which are both Boryong strains of O. tsutsugamushi. Also, clustering analyses including these two isolates gave slightly different results depending on whether they were clustered based on virulence genes or on the 56 kDa protein sequences. Consequently, we conclude that fatality rates in O. tsutsugamushi are correlated with differences in both serotypes and virulence genes. We identified some variations within the virulence genes dnaA, virB8, tolR, and trxA among the isolates.
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49
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Lin TY. Protein–protein interaction as a powering source of oxidoreductive reactivity. MOLECULAR BIOSYSTEMS 2010; 6:1454-62. [DOI: 10.1039/b927132e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Basu D, Khare G, Singh S, Tyagi A, Khosla S, Mande SC. A novel nucleoid-associated protein of Mycobacterium tuberculosis is a sequence homolog of GroEL. Nucleic Acids Res 2009; 37:4944-54. [PMID: 19528065 PMCID: PMC2731897 DOI: 10.1093/nar/gkp502] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Mycobacterium tuberculosis genome sequence reveals remarkable absence of many nucleoid-associated proteins (NAPs), such as HNS, Hfq or DPS. In order to characterize the nucleoids of M. tuberculosis, we have attempted to identify NAPs, and report an interesting finding that a chaperonin-homolog, GroEL1, is nucleoid associated. We report that M. tuberculosis GroEL1 binds DNA with low specificity but high affinity, suggesting that it might have naturally evolved to bind DNA. We are able to demonstrate that GroEL1 can effectively function as a DNA-protecting agent against DNase I or hydroxyl-radicals. Moreover, Atomic Force Microscopic studies reveal that GroEL1 can condense a large DNA into a compact structure. We also provide in vivo evidences that include presence of GroEL1 in purified nucleoids, in vivo crosslinking followed by Southern hybridizations and immunofluorescence imaging in M. tuberculosis confirming that GroEL1: DNA interactions occur in natural biological settings. These findings therefore reveal that M. tuberculosis GroEL1 has evolved to be associated with nucleoids.
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Affiliation(s)
- Debashree Basu
- Laboratory of Structural Biology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500001, India
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