1
|
Hong L, Wei L, Fanglan G, Jiao L, Shiheng T, Hong Y, Yao R, Xinyue G, Can Y. Unveiling the regulatory mechanism of poly-γ-glutamic acid on soil characteristics under drought stress through integrated metagenomics and metabolomics analysis. Front Microbiol 2024; 15:1387223. [PMID: 38751715 PMCID: PMC11094619 DOI: 10.3389/fmicb.2024.1387223] [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: 02/19/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
It is of utmost importance to understand the characteristics and regulatory mechanisms of soil in order to optimize soil management and enhance crop yield. Poly-γ-glutamic acid (γ-PGA), a stress-resistant amino acid polymer, plays a crucial role in plant drought stress resistance. However, little is known about the effects of γ-PGA on soil characteristics during drought treatments. In this study, the effects of different forms of γ-PGA on soil texture and basic physical and chemical properties under short-term drought conditions were investigated. Furthermore, the impact of γ-PGA on the microbial community and metabolic function of maize was analyzed. Under drought conditions, the introduction of γ-PGA into the soil resulted in notable improvements in the mechanical composition ratio and infiltration capacity of the soil. Concurrently, this led to a reduction in soil bulk density and improved soil organic matter content and fertility. Additionally, metagenomic analysis revealed that under drought conditions, the incorporation of γ-PGA into the soil enhanced the soil microbiota structure. This shift led to the predominance of bacteria that are crucial for carbon, nitrogen, and phosphorus cycles in the soil. Metabolomics analysis revealed that under drought treatment, γ-PGA affected soil metabolic patterns, with a particular focus on alterations in amino acid and vitamin metabolism pathways. Correlation analysis between the soil metagenome and metabolites showed that microorganisms played a significant role in metabolite accumulation. These results demonstrated that γ-PGA could improve soil characteristics under drought conditions and play an important role in soil microorganisms and microbial metabolism, providing further insights into the changes in soil characteristics under drought conditions.
Collapse
Affiliation(s)
- Li Hong
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Li Wei
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Ge Fanglan
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Li Jiao
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Tu Shiheng
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Yang Hong
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Ren Yao
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Gong Xinyue
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Yao Can
- Key Laboratory of the Evaluation and Monitoring of Southwest Land Resources (Ministry of Education), Sichuan Normal University, Chengdu, China
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| |
Collapse
|
2
|
Adolph C, Cheung CY, McNeil MB, Jowsey WJ, Williams ZC, Hards K, Harold LK, Aboelela A, Bujaroski RS, Buckley BJ, Tyndall JDA, Li Z, Langer JD, Preiss L, Meier T, Steyn AJC, Rhee KY, Berney M, Kelso MJ, Cook GM. A dual-targeting succinate dehydrogenase and F 1F o-ATP synthase inhibitor rapidly sterilizes replicating and non-replicating Mycobacterium tuberculosis. Cell Chem Biol 2024; 31:683-698.e7. [PMID: 38151019 DOI: 10.1016/j.chembiol.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/13/2023] [Accepted: 12/04/2023] [Indexed: 12/29/2023]
Abstract
Mycobacterial bioenergetics is a validated target space for antitubercular drug development. Here, we identify BB2-50F, a 6-substituted 5-(N,N-hexamethylene)amiloride derivative as a potent, multi-targeting bioenergetic inhibitor of Mycobacterium tuberculosis. We show that BB2-50F rapidly sterilizes both replicating and non-replicating cultures of M. tuberculosis and synergizes with several tuberculosis drugs. Target identification experiments, supported by docking studies, showed that BB2-50F targets the membrane-embedded c-ring of the F1Fo-ATP synthase and the catalytic subunit (substrate-binding site) of succinate dehydrogenase. Biochemical assays and metabolomic profiling showed that BB2-50F inhibits succinate oxidation, decreases the activity of the tricarboxylic acid (TCA) cycle, and results in succinate secretion from M. tuberculosis. Moreover, we show that the lethality of BB2-50F under aerobic conditions involves the accumulation of reactive oxygen species. Overall, this study identifies BB2-50F as an effective inhibitor of M. tuberculosis and highlights that targeting multiple components of the mycobacterial respiratory chain can produce fast-acting antimicrobials.
Collapse
Affiliation(s)
- Cara Adolph
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Matthew B McNeil
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - William J Jowsey
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand
| | - Zoe C Williams
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Kiel Hards
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Liam K Harold
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand
| | - Ashraf Aboelela
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Richard S Bujaroski
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Benjamin J Buckley
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Joel D A Tyndall
- School of Pharmacy, University of Otago, Dunedin 9054, New Zealand
| | - Zhengqiu Li
- School of Pharmacy, Jinan University, Guangzhou, China
| | - Julian D Langer
- Proteomics, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Laura Preiss
- Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Strasse 3, 60438 Frankfurt am Main, Germany
| | - Thomas Meier
- Department of Life Sciences, Imperial College London, Exhibition Road, London SW7 2AZ, UK; Private University in the Principality of Liechtenstein, Triesen, Liechtenstein
| | - Adrie J C Steyn
- Africa Health Research Institute, University of KwaZulu Natal, Durban, KwaZulu, Natal, South Africa; Department of Microbiology, Centers for AIDs Research and Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Kyu Y Rhee
- Department of Microbiology and Immunology, Weill Cornell Medicine, Cornell University, Ithaca, NY 14853, USA; Division of Infectious Diseases, Department of Medicine, Weill Cornell Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, New York, NY, USA
| | - Michael J Kelso
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW 2522, Australia; Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Gregory M Cook
- Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1042, New Zealand.
| |
Collapse
|
3
|
Shyam M, Kumar S, Singh V. Unlocking Opportunities for Mycobacterium leprae and Mycobacterium ulcerans. ACS Infect Dis 2024; 10:251-269. [PMID: 38295025 PMCID: PMC10862552 DOI: 10.1021/acsinfecdis.3c00371] [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: 07/31/2023] [Revised: 12/25/2023] [Accepted: 12/28/2023] [Indexed: 02/02/2024]
Abstract
In the recent decade, scientific communities have toiled to tackle the emerging burden of drug-resistant tuberculosis (DR-TB) and rapidly growing opportunistic nontuberculous mycobacteria (NTM). Among these, two neglected mycobacteria species of the Acinetobacter family, Mycobacterium leprae and Mycobacterium ulcerans, are the etiological agents of leprosy and Buruli ulcer infections, respectively, and fall under the broad umbrella of neglected tropical diseases (NTDs). Unfortunately, lackluster drug discovery efforts have been made against these pathogenic bacteria in the recent decade, resulting in the discovery of only a few countable hits and majorly repurposing anti-TB drug candidates such as telacebec (Q203), P218, and TB47 for current therapeutic interventions. Major ignorance in drug candidate identification might aggravate the dramatic consequences of rapidly spreading mycobacterial NTDs in the coming days. Therefore, this Review focuses on an up-to-date account of drug discovery efforts targeting selected druggable targets from both bacilli, including the accompanying challenges that have been identified and are responsible for the slow drug discovery. Furthermore, a succinct discussion of the all-new possibilities that could be alternative solutions to mitigate the neglected mycobacterial NTD burden and subsequently accelerate the drug discovery effort is also included. We anticipate that the state-of-the-art strategies discussed here may attract major attention from the scientific community to navigate and expand the roadmap for the discovery of next-generation therapeutics against these NTDs.
Collapse
Affiliation(s)
- Mousumi Shyam
- Department
of Pharmaceutical Sciences & Technology, Birla Institute of Technology, Mersa, Ranchi, Jharkhand 835215, India
| | - Sumit Kumar
- Holistic
Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
| | - Vinayak Singh
- Holistic
Drug Discovery and Development (H3D) Centre, University of Cape Town, Rondebosch 7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, University of Cape Town, Rondebosch 7701, South Africa
- Institute
of Infectious Disease and Molecular Medicine (IDM), University of Cape Town, Observatory 7925, Cape Town, South Africa
| |
Collapse
|
4
|
Choi SR, Narayanasamy P. In Vitro and In Vivo Antimicrobial Activity of an Oxidative Stress-Mediated Bicyclic Menaquinone Biosynthesis Inhibitor against MRSA. ACS Infect Dis 2023; 9:2016-2024. [PMID: 37655755 DOI: 10.1021/acsinfecdis.3c00319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
Menaquinone (MK) is an essential component in the oxidative phosphorylation pathway of Gram-positive bacteria. Drugs targeting enzymes involved in MK biosynthesis can prevent electron transfer, which leads to ATP starvation and thereby death of microorganisms. Previously, we reported a series of MenA inhibitors and demonstrated their antimicrobial activity against Gram-positive bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA) and mycobacteria. These inhibitors were developed by mimicking demethylmenaquinone, a product of MenA enzymatic reaction in MK biosynthesis. In this study, compound NM4, MK biosynthesis inhibitor, inhibited the formation of MRSA biofilm and it was screened against 1952 transposon mutants to elucidate mechanisms of action; however, no resistant mutants were found. Also, compound NM4 induced the production of reactive oxygen species (ROS) by blocking electron transfer in the oxidative phosphorylation pathway as observed by MRSA growth recovery using various ROS scavengers. An oxygen consumption assay also showed that NM4 blocks the oxygen consumption by MRSA, but the addition of menaquinone (MK) restores growth of MRSA. The NM4-treated MRSA induced the expression of catalase by more than 25%, as quantified by the native gel. A pulmonary murine model exhibited that NM4 significantly reduced bacterial lung load in mice without toxicity. An NM4-resistant USA300 strain was developed to attempt to identify the targets participating in the mechanism of resistance. Our results support that respiration and oxidative phosphorylation are potential targets for developing antimicrobial agents against MRSA. Altogether, our findings suggest the potential use of MK biosynthesis inhibitors as an effective antimicrobial agent against MRSA.
Collapse
Affiliation(s)
- Seoung-Ryoung Choi
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| | - Prabagaran Narayanasamy
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska 68198, United States
| |
Collapse
|
5
|
Kadeřábková N, Mahmood AJS, Furniss RCD, Mavridou DAI. Making a chink in their armor: Current and next-generation antimicrobial strategies against the bacterial cell envelope. Adv Microb Physiol 2023; 83:221-307. [PMID: 37507160 PMCID: PMC10517717 DOI: 10.1016/bs.ampbs.2023.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Gram-negative bacteria are uniquely equipped to defeat antibiotics. Their outermost layer, the cell envelope, is a natural permeability barrier that contains an array of resistance proteins capable of neutralizing most existing antimicrobials. As a result, its presence creates a major obstacle for the treatment of resistant infections and for the development of new antibiotics. Despite this seemingly impenetrable armor, in-depth understanding of the cell envelope, including structural, functional and systems biology insights, has promoted efforts to target it that can ultimately lead to the generation of new antibacterial therapies. In this article, we broadly overview the biology of the cell envelope and highlight attempts and successes in generating inhibitors that impair its function or biogenesis. We argue that the very structure that has hampered antibiotic discovery for decades has untapped potential for the design of novel next-generation therapeutics against bacterial pathogens.
Collapse
Affiliation(s)
- Nikol Kadeřábková
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - Ayesha J S Mahmood
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States
| | - R Christopher D Furniss
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Despoina A I Mavridou
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, United States; John Ring LaMontagne Center for Infectious Diseases, The University of Texas at Austin, Austin, TX, United States.
| |
Collapse
|
6
|
Kelam LM, Wani MA, Dhaked DK. An update on ATP synthase inhibitors: A unique target for drug development in M. tuberculosis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:87-104. [PMID: 37105260 DOI: 10.1016/j.pbiomolbio.2023.04.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 04/29/2023]
Abstract
ATP synthase is a key protein in the oxidative phosphorylation process, as it aids in the effective production of ATP (Adenosine triphosphate) in all life's of kingdoms. ATP synthases have distinctive properties that contribute to efficient ATP synthesis. The ATP synthase of mycobacterium is of special relevance since it has been identified as a target for potential anti-TB molecules, especially Bedaquiline (BDQ). Better knowledge of how mycobacterial ATP synthase functions and its peculiar characteristics will aid in our understanding of bacterial energy metabolism adaptations. Furthermore, identifying and understanding the important distinctions between human ATP synthase and bacterial ATP synthase may provide insight into the design and development of inhibitors that target specific ATP synthase. In recent years, many potential candidates targeting the ATP synthase of mycobacterium have been developed. In this review, we discuss the druggable targets of the Electron transport chain (ETC) and recently identified potent inhibitors (including clinical molecules) from 2015 to 2022 of diverse classes that target ATP synthase of M. tuberculosis.
Collapse
Affiliation(s)
- Lakshmi Mounika Kelam
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India
| | - Mushtaq Ahmad Wani
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India
| | - Devendra K Dhaked
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER)-Kolkata, Chunilal Bhawan, 168 Maniktala Main Road, Kolkata, 700054, West Bengal, India.
| |
Collapse
|
7
|
Imran M, Alotaibi NM, Thabet HK, Alruwaili JA, Asdaq SMB, Eltaib L, Alshehri A, Alsaiari AA, Almehmadi M, Alshammari ABH, Alshammari AM. QcrB inhibition as a potential approach for the treatment of tuberculosis: A review of recent developments, patents, and future directions. J Infect Public Health 2023; 16:928-937. [PMID: 37086552 DOI: 10.1016/j.jiph.2023.04.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/28/2023] [Accepted: 04/11/2023] [Indexed: 04/24/2023] Open
Abstract
The unmet medical need for drug-resistant tuberculosis (DRTB) is a significant concern. Accordingly, identifying new drug targets for tuberculosis (TB) treatment and developing new therapies based on these drug targets is one of the strategies to tackle DRTB. QcrB is an innovative drug target to create treatments for DRTB. This article highlights QcrB inhibitors and their therapeutic compositions for treating TB. The literature for this article was gathered from PubMed and free patent databases utilizing different keywords related to QcrB inhibitor-based inventions. The data was collected from the conceptualization of telacebec (2010) QcrB to December 2022. A little interesting and encouraging research has been performed on QcrB inhibitors. Telacebec and TB47 are established QcrB inhibitors in the clinical trial. The inventive QcrB inhibitor-based drug combinations can potentially handle DRTB and reduce the TB therapy duration. The authors anticipate great opportunities in fostering QcrB inhibitor-based patentable pharmaceutical inventions against TB. Drug repurposing can be a promising strategy to get safe and effective QcrB inhibitors. However, developing drug resistance, drug tolerance, and selectivity of QcrB inhibitors for Mtb will be the main challenges in developing effective QcrB inhibitors. In conclusion, QcrB is a promising drug target for developing effective treatments for active, latent, and drug-resistant TB. Many inventive and patentable combinations and compositions of QcrB inhibitors with other anti-TB drugs are anticipated as future treatments for TB.
Collapse
Affiliation(s)
- Mohd Imran
- Department of Pharmaceutical Chemistry, College of Pharmacy, Northern Border University, Rafha 91911, Saudi Arabia.
| | - Nawaf M Alotaibi
- Department of Clinical Pharmacy, College of Pharmacy, Northern Border University, Rafha 91911, Saudi Arabia; Chemistry Department, College of Sciences and Arts, Northern Border University, Rafha 91911, Saudi Arabia
| | - Hamdy K Thabet
- Chemistry Department, College of Sciences and Arts, Northern Border University, Rafha 91911, Saudi Arabia
| | - Jamal A Alruwaili
- College of Applied Medical Sciences, Medical Lab Technology Department, Northern Border University, Arar 91431, Saudi Arabia
| | - Syed M B Asdaq
- Department of Pharmacy Practice, College of Pharmacy, AlMaarefa University, Dariyah, Riyadh 13713, Saudi Arabia
| | - Lina Eltaib
- Department of Pharmaceutics, College of Pharmacy, Northern Border University, Rafha 91911, Saudi Arabia
| | - Ahmed Alshehri
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Northern Border University, Rafha, Saudi Arabia; Department of Pharmacology, College of Clinical Pharmacy, Imam Abdulrahman Bin Faisal University, King Faisal Road, Dammam 31441, Saudi Arabia
| | - Ahad A Alsaiari
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | - Mazen Almehmadi
- Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Taif University, P.O. Box 11099, Taif 21944, Saudi Arabia
| | | | | |
Collapse
|
8
|
Liang Y, Plourde A, Bueler SA, Liu J, Brzezinski P, Vahidi S, Rubinstein JL. Structure of mycobacterial respiratory complex I. Proc Natl Acad Sci U S A 2023; 120:e2214949120. [PMID: 36952383 PMCID: PMC10068793 DOI: 10.1073/pnas.2214949120] [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: 09/04/2022] [Accepted: 02/10/2023] [Indexed: 03/24/2023] Open
Abstract
Oxidative phosphorylation, the combined activity of the electron transport chain (ETC) and adenosine triphosphate synthase, has emerged as a valuable target for the treatment of infection by Mycobacterium tuberculosis and other mycobacteria. The mycobacterial ETC is highly branched with multiple dehydrogenases transferring electrons to a membrane-bound pool of menaquinone and multiple oxidases transferring electrons from the pool. The proton-pumping type I nicotinamide adenine dinucleotide (NADH) dehydrogenase (Complex I) is found in low abundance in the plasma membranes of mycobacteria in typical in vitro culture conditions and is often considered dispensable. We found that growth of Mycobacterium smegmatis in carbon-limited conditions greatly increased the abundance of Complex I and allowed isolation of a rotenone-sensitive preparation of the enzyme. Determination of the structure of the complex by cryoEM revealed the "orphan" two-component response regulator protein MSMEG_2064 as a subunit of the assembly. MSMEG_2064 in the complex occupies a site similar to the proposed redox-sensing subunit NDUFA9 in eukaryotic Complex I. An apparent purine nucleoside triphosphate within the NuoG subunit resembles the GTP-derived molybdenum cofactor in homologous formate dehydrogenase enzymes. The membrane region of the complex binds acyl phosphatidylinositol dimannoside, a characteristic three-tailed lipid from the mycobacterial membrane. The structure also shows menaquinone, which is preferentially used over ubiquinone by gram-positive bacteria, in two different positions along the quinone channel, comparable to ubiquinone in other structures and suggesting a conserved quinone binding mechanism.
Collapse
Affiliation(s)
- Yingke Liang
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
| | - Alicia Plourde
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - Stephanie A. Bueler
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
| | - Jun Liu
- Department of Molecular Genetics, University of Toronto, TorontoM5S 1A8, Canada
| | - Peter Brzezinski
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91Stockholm, Sweden
| | - Siavash Vahidi
- Department of Molecular and Cellular Biology, University of Guelph, TorontoN1G 2W1, Canada
| | - John L. Rubinstein
- Molecular Medicine Program, The Hospital for Sick Children, TorontoM5G 0A4, Canada
- Department of Biochemistry, University of Toronto, TorontoM5S 1A8, Canada
- Department of Medical Biophysics, University of Toronto, TorontoM5G 1L7, Canada
| |
Collapse
|
9
|
Berg K, Hegde P, Pujari V, Brinkmann M, Wilkins DZ, Parish T, Crick DC, Aldrich CC. SAR study of piperidine derivatives as inhibitors of 1,4-dihydroxy-2-naphthoate isoprenyltransferase (MenA) from Mycobacterium tuberculosis. Eur J Med Chem 2023; 249:115125. [PMID: 36682292 PMCID: PMC9975056 DOI: 10.1016/j.ejmech.2023.115125] [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: 11/03/2022] [Revised: 01/11/2023] [Accepted: 01/14/2023] [Indexed: 01/19/2023]
Abstract
The electron transport chain (ETC) in the cell membrane consists of a series of redox complexes that transfer electrons from electron donors to acceptors and couples this electron transfer with the transfer of protons (H+) across a membrane. This process generates proton motive force which is used to produce ATP and a myriad of other functions and is essential for the long-term survival of Mycobacterium tuberculosis (Mtb), the causative organism of tuberculosis (TB), under the hypoxic conditions present within infected granulomas. Menaquinone (MK), an important carrier molecule within the mycobacterial ETC, is synthesized de novo by a cluster of enzymes known as the classic/canonical MK biosynthetic pathway. MenA (1,4-dihydroxy-2-naphthoate prenyltransferase), the antepenultimate enzyme in this pathway, is a verified target for TB therapy. In this study, we explored structure-activity relationships of a previously discovered MenA inhibitor scaffold, seeking to improve potency and drug disposition properties. Focusing our campaign upon three molecular regions, we identified two novel inhibitors with potent activity against MenA and Mtb (IC50 = 13-22 μM, GIC50 = 8-10 μM). These analogs also displayed substantially improved pharmacokinetic parameters and potent synergy with other ETC-targeting agents, achieving nearly complete sterilization of Mtb in combination therapy within two weeks in vivo. These new inhibitors of MK biosynthesis present a promising new strategy to curb the continued spread of TB.
Collapse
Affiliation(s)
- Kaja Berg
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, MN, 55455, USA
| | - Pooja Hegde
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, MN, 55455, USA
| | - Venugopal Pujari
- Mycobacteria Research Laboratories, Microbiology, Immunology, and Pathology Department, Colorado State University, Fort Collins, CO, 80523, USA
| | - Marzena Brinkmann
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, MN, 55455, USA
| | - David Z Wilkins
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, 98109, USA
| | - Tanya Parish
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, 98109, USA
| | - Dean C Crick
- Mycobacteria Research Laboratories, Microbiology, Immunology, and Pathology Department, Colorado State University, Fort Collins, CO, 80523, USA.
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, MN, 55455, USA.
| |
Collapse
|
10
|
Pujari V, Rozman K, Dhiman RK, Aldrich CC, Crick DC. Mycobacterial MenG: Partial Purification, Characterization, and Inhibition. ACS Infect Dis 2022; 8:2430-2440. [PMID: 36417754 DOI: 10.1021/acsinfecdis.2c00190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Menaquinone (MK) is an essential component of the electron transport chain (ETC) in the gram-variable Mycobacterium tuberculosis and many Gram-positive pathogens. Three genes in the M. tuberculosis genome were annotated as methyltransferases involved in lipoquinone synthesis in mycobacteria. Heterologous expression of Rv0558 complemented an ubiE (the quinone C-methyltransferase involved in ubiquinone and menaquinone synthesis) deletion in Escherichia coli, and expression in a wild-type E. coli strain increased quinone C-methyltransferase specific activity by threefold. Rv0558 encodes a canonical C-methyltransferase or, more specifically, a S-adenosylmethionine/demethylmenaquinol methyltransferase. Partially purified recombinant protein catalyzed the formation of MK from demethylmenaquinone (DMK), although the activity of the recombinant protein was low and appeared to require a cofactor or intact membrane structure for activity. Membrane preparations from irradiated M. tuberculosis also showed poor activity; however, membrane preparations from wild-type Mycobacterium smegmatis showed robust, substrate-dependent activity. The apparent Km values for demethylmenaquinone and SAM were 14 ± 5.0 and 17 ± 7.0 μM, respectively. Interestingly, addition of dithiothreitol, dithionite, NADH, or other substrates of primary dehydrogenases to reaction mixtures containing membrane preparations stimulated the activity. Thus, these observations strongly suggest that demethylmenaquinol is the actual substrate of MenG. Ro 48-8071, previously reported to inhibit mycobacterial MK synthesis and growth, inhibited Rv0558 activity with an IC50 value of 5.1 ± 0.5 μM, and DG70 (GSK1733953A), first described as a respiration inhibitor in M. tuberculosis, inhibits MenG activity with an IC50 value of 2.6 ± 0.6 μM.
Collapse
Affiliation(s)
- Venugopal Pujari
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Kaja Rozman
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Rakesh K Dhiman
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Courtney C Aldrich
- Department of Medicinal Chemistry, University of Minnesota, 308 Harvard Street Southeast, Minneapolis, Minnesota 55455, United States
| | - Dean C Crick
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| |
Collapse
|
11
|
McNeil MB, Cheung CY, Waller NJE, Adolph C, Chapman CL, Seeto NEJ, Jowsey W, Li Z, Hameed HMA, Zhang T, Cook GM. Uncovering interactions between mycobacterial respiratory complexes to target drug-resistant Mycobacterium tuberculosis. Front Cell Infect Microbiol 2022; 12:980844. [PMID: 36093195 PMCID: PMC9461714 DOI: 10.3389/fcimb.2022.980844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/03/2022] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis remains a leading cause of infectious disease morbidity and mortality for which new drug combination therapies are needed. Mycobacterial bioenergetics has emerged as a promising space for the development of novel therapeutics. Further to this, unique combinations of respiratory inhibitors have been shown to have synergistic or synthetic lethal interactions, suggesting that combinations of bioenergetic inhibitors could drastically shorten treatment times. Realizing the full potential of this unique target space requires an understanding of which combinations of respiratory complexes, when inhibited, have the strongest interactions and potential in a clinical setting. In this review, we discuss (i) chemical-interaction, (ii) genetic-interaction and (iii) chemical-genetic interaction studies to explore the consequences of inhibiting multiple mycobacterial respiratory components. We provide potential mechanisms to describe the basis for the strongest interactions. Finally, whilst we place an emphasis on interactions that occur with existing bioenergetic inhibitors, by highlighting interactions that occur with alternative respiratory components we envision that this information will provide a rational to further explore alternative proteins as potential drug targets and as part of unique drug combinations.
Collapse
Affiliation(s)
- Matthew B. McNeil
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
| | - Chen-Yi Cheung
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Natalie J. E. Waller
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cara Adolph
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Cassandra L. Chapman
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Noon E. J. Seeto
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - William Jowsey
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Zhengqiu Li
- School of Pharmacy, Jinan University, Guangzhou, China
| | - H. M. Adnan Hameed
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Tianyu Zhang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- China-New Zealand Joint Laboratory of Biomedicine and Health, Guangzhou Institutes of Biomedicine and Health (GIBH), Chinese Academy of Sciences (CAS), Guangzhou, China
- Guangdong-Hong Kong-Macau Joint Laboratory of Respiratory Infectious Diseases, Guangzhou, China
- University of Chinese Academy of Sciences (UCAS), Beijing, China
| | - Gregory M. Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
- Maurice Wilkins, Centre for Molecular Biodiscovery, The University of Auckland, Auckland, New Zealand
- *Correspondence: Matthew B. McNeil, ; Gregory M. Cook,
| |
Collapse
|
12
|
Bandyopadhyay P, Pramanick I, Biswas R, PS S, Sreedharan S, Singh S, Rajmani RS, Laxman S, Dutta S, Singh A. S-Adenosylmethionine-responsive cystathionine β-synthase modulates sulfur metabolism and redox balance in Mycobacterium tuberculosis. SCIENCE ADVANCES 2022; 8:eabo0097. [PMID: 35749503 PMCID: PMC9232105 DOI: 10.1126/sciadv.abo0097] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 05/09/2022] [Indexed: 05/10/2023]
Abstract
Methionine and cysteine metabolisms are important for the survival and pathogenesis of Mycobacterium tuberculosis (Mtb). The transsulfuration pathway converts methionine to cysteine and represents an important link between antioxidant and methylation metabolism in diverse organisms. Using a combination of biochemistry and cryo-electron microscopy, we characterized the first enzyme of the transsulfuration pathway, cystathionine β-synthase (MtbCbs) in Mtb. We demonstrated that MtbCbs is a heme-less, pyridoxal-5'-phosphate-containing enzyme, allosterically activated by S-adenosylmethionine (SAM). The atomic model of MtbCbs in its native and SAM-bound conformations revealed a unique mode of SAM-dependent allosteric activation. Further, SAM stabilized MtbCbs by sterically occluding proteasomal degradation, which was crucial for supporting methionine and redox metabolism in Mtb. Genetic deficiency of MtbCbs reduced Mtb survival upon homocysteine overload in vitro, inside macrophages, and in mice coinfected with HIV. Thus, the MtbCbs-SAM axis constitutes an important mechanism of coordinating sulfur metabolism in Mtb.
Collapse
Affiliation(s)
- Parijat Bandyopadhyay
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Ishika Pramanick
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Rupam Biswas
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Sabarinath PS
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka 560065, India
| | - Sreesa Sreedharan
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka 560065, India
| | - Shalini Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Raju S. Rajmani
- Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Sunil Laxman
- Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka 560065, India
| | - Somnath Dutta
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Amit Singh
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India
- Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, Karnataka 560012, India
| |
Collapse
|
13
|
Rifampicin-Mediated Metabolic Changes in Mycobacterium tuberculosis. Metabolites 2022; 12:metabo12060493. [PMID: 35736426 PMCID: PMC9228056 DOI: 10.3390/metabo12060493] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 05/13/2022] [Accepted: 05/24/2022] [Indexed: 11/17/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is considered to be a devastating pathogen worldwide, affecting millions of people globally. Several drugs targeting distinct pathways are utilized for the treatment of tuberculosis. Despite the monumental efforts being directed at the discovery of drugs for Mtb, the pathogen has also developed mechanisms to evade the drug action and host processes. Rifampicin was an early anti-tuberculosis drug, and is still being used as the first line of treatment. This study was carried out in order to characterize the in-depth rifampicin-mediated metabolic changes in Mtb, facilitating a better understanding of the physiological processes based on the metabolic pathways and predicted protein interactors associated with the dysregulated metabolome. Although there are various metabolomic studies that have been carried out on rifampicin mutants, this is the first study that reports a large number of significantly altered metabolites in wild type Mtb upon rifampicin treatment. In this study, a total of 173 metabolites, associated with pyrimidine, purine, arginine, phenylalanine, tyrosine, and tryptophan metabolic pathways, were significantly altered by rifampicin. The predicted host protein interactors of the rifampicin-dysregulated Mtb metabolome were implicated in transcription, inflammation, apoptosis, proteolysis, and DNA replication. Further, tricarboxylic acidcycle metabolites, arginine, and phosphoenolpyruvate were validated by multiple-reaction monitoring. This study provides a comprehensive list of altered metabolites that serves as a basis for understanding the rifampicin-mediated metabolic changes, and associated functional processes, in Mtb, which holds therapeutic potential for the treatment of Mtb.
Collapse
|
14
|
Barman A, Patra MM, Das Gupta SK. The respiratory lipoquinone, menaquinone, functions as an inducer of genes regulated by the Mycobacterium smegmatis repressor MSMEG_2295. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35575764 DOI: 10.1099/mic.0.001192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A previous study reported that the Mycobacterium smegmatis (Msm) protein MSMEG_2295 is a repressor controlling the expression of several genes, including that for MSMEG_5125, a putative isoprenoid binding protein belonging to the YceI family, and DinB2, a DNA damage repair enzyme. This repressor is encoded by the first gene of the operon that also expresses the gene for DinB2. Targeted inhibition of MSMEG_5125 using CRISPRi technology resulted in a significant loss of Msm's respiratory activity and viability. Since this protein has been predicted to be an isoprenoid binding protein, we suspected a role of menaquinones, which are isoprenoid naphthoquinones, in the observed phenomenon. Accordingly, we tested whether MSMEG_5125's deficiency-induced lethality could be reversed by adding menaquinone. The result was positive, implying cooperation between MSMEG_5125 and menaquinone in bringing about respiration. Inhibition of MSMEG_5125 expression led to the induction of MSMEG_0089 and 2296, two hallmark genes of the MSMEG_2295 regulon. This result suggests that when MSMEG_5125 becomes limiting, a feedback-loop derepresses the MSMEG_2295 regulon genes, including its own. Interestingly, menaquinone functioned as an inducer of MSMEG_5125, indicating that it is likely to mediate the feedback mechanism. This result also strengthens our hypothesis that the functions of menaquinone and MSMEG_5125 are interrelated. Menaquinone also induced the MSMEG_2295-controlled operon MSMEG_2295-2294 (dinB2) not induced following the inactivation of MSMEG_5125. Therefore, the activation mechanism of MSMEG_2295-regulated genes may not be the same for all, although derepression is likely to be a common feature. In vitro, menaquinone abolished MSMEG_2295's DNA binding activity by interacting with it, confirming its role as an inducer. Therefore, a menaquinone-MSMEG_5125-regulated gene expression circuit controls Msm respiration and possibly oxidative stress-induced DNA damage repair.
Collapse
Affiliation(s)
- Anik Barman
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Madhu Manti Patra
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| | - Sujoy K Das Gupta
- Department of Microbiology, Bose Institute, P-1/12 C.I.T. Scheme VIIM, Kolkata 700054, India
| |
Collapse
|
15
|
Swaminath S, Pradhan A, Nair RR, Ajitkumar P. Deletion of rifampicin-inactivating mono-ADP-ribosyl transferase gene of Mycobacterium smegmatis globally altered gene expression profile that favoured increase in ROS levels and thereby antibiotic resister generation. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100142. [PMID: 35909599 PMCID: PMC9325912 DOI: 10.1016/j.crmicr.2022.100142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 05/21/2022] [Accepted: 05/29/2022] [Indexed: 10/31/2022] Open
Abstract
Physiological role of mono-ADP-ribosyl transferase (Arr) of Mycobacterium smegmatis revealed. Arr is required to maintain ROS levels in actively growing M. smegmatis. Arr influences gene expression at global level in several pathways. Expression of electron transfer, antioxidation, and DNA repair genes are influenced by Arr. Arr is required to maintain an optimal oxidative and metabolic status.
The physiological role of mono-ADP-ribosyl transferase (Arr) of Mycobacterium smegmatis, which inactivates rifampicin, remains unclear. An earlier study reported increased expression of arr during oxidative stress and DNA damage. This suggested a role for Arr in the oxidative status of the cell and its associated effect on DNA damage. Since reactive oxygen species (ROS) influence oxidative status, we investigated whether Arr affected ROS levels in M. smegmatis. Significantly elevated levels of superoxide and hydroxyl radical were found in the mid-log phase (MLP) cultures of the arr knockout strain (arr-KO) as compared those in the wild-type strain (WT). Complementation of arr-KO with expression from genomically integrated arr under its native promoter restored the levels of ROS equivalent to that in WT. Due to the inherently high ROS levels in the actively growing arr-KO, rifampicin resisters with rpoB mutations could be selected at 0 hr of exposure itself against rifampicin, unlike in the WT where the resisters emerged at 12th hr of rifampicin exposure. Microarray analysis of the actively growing cultures of arr-KO revealed significantly high levels of expression of genes from succinate dehydrogenase I and NADH dehydrogenase I operons, which would have contributed to the increased superoxide levels. In parallel, expression of specific DNA repair genes was significantly decreased, favouring retention of the mutations inflicted by the ROS. Expression of several metabolic pathway genes also was significantly altered. These observations revealed that Arr was required for maintaining a gene expression profile that would provide optimum levels of ROS and DNA repair system in the actively growing M. smegmatis.
Collapse
|
16
|
Choi SR, Narayanasamy P. Synthesis, optimization, in vitro and in vivo study of bicyclic substituted amine as MenA inhibitor. Bioorg Med Chem Lett 2021; 47:128203. [PMID: 34139327 DOI: 10.1016/j.bmcl.2021.128203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/10/2021] [Indexed: 11/16/2022]
Abstract
Menaquinone (MK) plays essential role in the electron transport chain (ETC), suggesting MK biosynthesis enzymes as potential targets for drug development. Previously, we demonstrated that Methicillin-resistant Staphylococcus aureus (MRSA) is susceptible to naphthol-based compounds which were developed by mimicking demethylmenaquinone, a product of MenA enzymatic reaction. Here, a series of new MenA inhibitors (4-19) were synthesized and evaluated as MenA inhibitors in this study. The inhibitors were designed to improve growth inhibitory activity against MRSA. Among the MenA inhibitors, bicyclic substituted amine 3 showed MIC of 3 µg/mL, and alkenyl substituted amine 11 showed MIC of 8 µg/mL against USA300. Regrowth of MRSA was observed on addition of MK when exposed to 8 µg/mL of inhibitor 11, supporting inhibition of MK biosynthesis. However, inhibitor 11 did not show efficacy in treating USA300 infected C. elegans up to 25 µg/mL concentration. However, all infected C. elegans survived when exposed to a bicyclic substituted amine 3. Hence, a bicyclic substituted amine was tested in mice for tolerability and biodistribution and observed 100% tolerable and high level of compound accumulation in lungs.
Collapse
Affiliation(s)
- Seoung-Ryoung Choi
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Prabagaran Narayanasamy
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA.
| |
Collapse
|
17
|
Bose P, Harit AK, Das R, Sau S, Iyer AK, Kashaw SK. Tuberculosis: current scenario, drug targets, and future prospects. Med Chem Res 2021. [DOI: 10.1007/s00044-020-02691-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
18
|
Hasenoehrl EJ, Wiggins TJ, Berney M. Bioenergetic Inhibitors: Antibiotic Efficacy and Mechanisms of Action in Mycobacterium tuberculosis. Front Cell Infect Microbiol 2021; 10:611683. [PMID: 33505923 PMCID: PMC7831573 DOI: 10.3389/fcimb.2020.611683] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 11/23/2020] [Indexed: 11/23/2022] Open
Abstract
Development of novel anti-tuberculosis combination regimens that increase efficacy and reduce treatment timelines will improve patient compliance, limit side-effects, reduce costs, and enhance cure rates. Such advancements would significantly improve the global TB burden and reduce drug resistance acquisition. Bioenergetics has received considerable attention in recent years as a fertile area for anti-tuberculosis drug discovery. Targeting the electron transport chain (ETC) and oxidative phosphorylation machinery promises not only to kill growing cells but also metabolically dormant bacilli that are inherently more drug tolerant. Over the last two decades, a broad array of drugs targeting various ETC components have been developed. Here, we provide a focused review of the current state of art of bioenergetic inhibitors of Mtb with an in-depth analysis of the metabolic and bioenergetic disruptions caused by specific target inhibition as well as their synergistic and antagonistic interactions with other drugs. This foundation is then used to explore the reigning theories on the mechanisms of antibiotic-induced cell death and we discuss how bioenergetic inhibitors in particular fail to be adequately described by these models. These discussions lead us to develop a clear roadmap for new lines of investigation to better understand the mechanisms of action of these drugs with complex mechanisms as well as how to leverage that knowledge for the development of novel, rationally-designed combination therapies to cure TB.
Collapse
Affiliation(s)
- Erik J Hasenoehrl
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Thomas J Wiggins
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Berney
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, United States
| |
Collapse
|
19
|
Small organic molecules targeting the energy metabolism of Mycobacterium tuberculosis. Eur J Med Chem 2020; 212:113139. [PMID: 33422979 DOI: 10.1016/j.ejmech.2020.113139] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 11/21/2022]
Abstract
Causing approximately 10 million incident cases and 1.3-1.5 million deaths every year, Mycobacterium tuberculosis remains a global health problem. The risk is further exacerbated with latent tuberculosis (TB) infection, the HIV pandemic, and increasing anti-TB drug resistance. Therefore, unexplored chemical scaffolds directed towards new molecular targets are increasingly desired. In this context, mycobacterial energy metabolism, particularly the oxidative phosphorylation (OP) pathway, is gaining importance. Mycobacteria possess primary dehydrogenases to fuel electron transport; aa3-type cytochrome c oxidase and bd-type menaquinol oxidase to generate a protonmotive force; and ATP synthase, which is essential for both growing mycobacteria as well as dormant mycobacteria because ATP is produced under both aerobic and hypoxic conditions. Small organic molecules targeting OP are active against latent TB as well as resistant TB strains. FDA approval of the ATP synthase inhibitor bedaquiline and the discovery of clinical candidate Q203, which both interfere with the cytochrome bc1 complex, have already confirmed mycobacterial energy metabolism to be a valuable anti-TB drug target. This review highlights both preferable molecular targets within mycobacterial OP and promising small organic molecules targeting OP. Progressive research in the area of mycobacterial OP revealed several highly potent anti-TB compounds with nanomolar-range MICs as low as 0.004 μM against Mtb H37Rv. Therefore, we are convinced that targeting the OP pathway can combat resistant TB and latent TB, leading to more efficient anti-TB chemotherapy.
Collapse
|
20
|
Blaise M, Kremer L. Self-control of vitamin K 2 production captured in the crystal. J Biol Chem 2020; 295:3771-3772. [PMID: 32198187 DOI: 10.1074/jbc.h120.013113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Menaquinone (MK) or vitamin K2 is an important metabolite that controls the redox/energy status of Mycobacterium tuberculosis Although the major steps of MK biosynthesis have been delineated, the regulatory mechanisms of this pathway have not been adequately explored. Bashiri et al. now demonstrate that MenD, catalyzing the first committed step of MK production, is allosterically inhibited by a downstream cytosolic metabolite in the MK biosynthesis pathway.
Collapse
Affiliation(s)
- Mickaël Blaise
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France
| | - Laurent Kremer
- Institut de Recherche en Infectiologie de Montpellier (IRIM), Université de Montpellier, CNRS UMR 9004, 34293 Montpellier, France .,INSERM, IRIM, 34293 Montpellier, France
| |
Collapse
|
21
|
Kumar S, Koehn JT, Gonzalez-Juarrero M, Crans DC, Crick DC. Mycobacterium tuberculosis Survival in J774A.1 Cells Is Dependent on MenJ Moonlighting Activity, Not Its Enzymatic Activity. ACS Infect Dis 2020; 6:2661-2671. [PMID: 32866371 DOI: 10.1021/acsinfecdis.0c00312] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MenJ, a flavoprotein oxidoreductase, is responsible for the saturation of the β-isoprene unit of mycobacterial menaquinone, resulting in the conversion of menaquinone with nine isoprene units (MK-9) to menaquinone with nine isoprene units where the double bond in the second unit is reduced [MK-9(II-H2)]. The hydrogenation of MK-9 increases the efficiency of the mycobacterial electron transport system, whereas the deletion of MenJ results in decreased survival of the bacteria inside J774A.1 macrophage-like cells but is not required for growth in culture. Thus, it was suggested that MenJ may represent a contextual drug target in M. tuberculosis, that is, a drug target that is valid only in the context of an infected macrophage. However, it was unclear if the conversion of MK-9 to MK-9(II-H2) or the MenJ protein itself was responsible for bacterial survival. In order to resolve this issue, a plasmid expressing folded, full-length, inactive MenJ was engineered. Primary sequence analysis data revealed that MenJ shares conserved FAD binding, NADH binding, and catalytic and C-terminal motifs with archaeal geranylgeranyl reductases. A MenJ mutant deficient in any one of these motifs is devoid of reductase activity. Therefore, point mutations of highly conserved amino acids in the conserved motifs were generated and the recombinant proteins were monitored for conformational changes by circular dichroism and oxidoreductase activity. The mutational analysis indicates that amino acids tryptophan 215 (W215) and cysteine 46 (C46) of M. tuberculosis MenJ, conserved in known archaeal geranylgeranyl reductases and putative menaquinone saturases, are essential to the hydrogenation of MK-9. The mutation of either C46 to serine (C46S) or W215 to leucine (W215L) in MenJ completely abolishes the catalytic activity in vitro, and menJ knockout strains of M. tuberculosis expressing either the C46S or W215L mutant protein are unable to convert MK-9 to MK-9(II-H2) but survive inside the J774A.1 cells. Thus, surprisingly, the survival of M. tuberculosis in J774A.1 cells is dependent on the expression of MenJ rather than its oxidoreductase activity, the conversion of MK-9 to MK-9(II-H2) as previously hypothesized. Overall, the current data suggest that MenJ is a moonlighting protein.
Collapse
|
22
|
Panthee S, Paudel A, Hamamoto H, Uhlemann AC, Sekimizu K. The Role of Amino Acid Substitution in HepT Toward Menaquinone Isoprenoid Chain Length Definition and Lysocin E Sensitivity in Staphylococcus aureus. Front Microbiol 2020; 11:2076. [PMID: 32983054 PMCID: PMC7479192 DOI: 10.3389/fmicb.2020.02076] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/06/2020] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES Staphylococcus aureus Smith strain is a historical strain widely used for research purposes in animal infection models for testing the therapeutic activity of antimicrobial agents. We found that it displayed higher sensitivity toward lysocin E, a menaquinone (MK) targeting antibiotic, compared to other S. aureus strains. Therefore, we further explored the mechanism of this hypersensitivity. METHODS MK production was analyzed by high-performance liquid chromatography and mass spectrometric analysis. S. aureus Smith genome sequence was completed using a hybrid assembly approach, and the MK biosynthetic genes were compared with other S. aureus strains. The hepT gene was cloned and introduced into S. aureus RN4220 strain using phage mediated recombination, and lysocin E sensitivity was analyzed by the measurement of colony-forming units. RESULTS We found that Smith strain produced MKs with the length of the side chain ranging between 8 and 10, as opposed to other S. aureus strains that produce MKs 7-9. We revealed that Smith strain possessed the classical pathway for MK biosynthesis like the other S. aureus. HepT, a polyprenyl diphosphate synthase involved in chain elongation of isoprenoid, in Smith strain harbored a Q25P substitution. Introduction of hepT from Smith to RN4220 led to the production of MK-10 and an increased sensitivity toward lysocin E. CONCLUSION We found that HepT was responsible for the definition of isoprenoid chain length of MKs and antibiotic sensitivity.
Collapse
Affiliation(s)
- Suresh Panthee
- Teikyo University Institute of Medical Mycology, Hachioji, Japan
| | - Atmika Paudel
- Teikyo University Institute of Medical Mycology, Hachioji, Japan
| | - Hiroshi Hamamoto
- Teikyo University Institute of Medical Mycology, Hachioji, Japan
| | - Anne-Catrin Uhlemann
- Department of Medicine, Columbia University Medical Center, New York, NY, United States
| | | |
Collapse
|
23
|
Ngcobo NS, Chiliza ZE, Chen W, Yu JH, Nelson DR, Tuszynski JA, Preto J, Syed K. Comparative Analysis, Structural Insights, and Substrate/Drug Interaction of CYP128A1 in Mycobacterium tuberculosis. Int J Mol Sci 2020; 21:E4816. [PMID: 32650369 PMCID: PMC7404182 DOI: 10.3390/ijms21144816] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022] Open
Abstract
Cytochrome P450 monooxygenases (CYPs/P450s) are well known for their role in organisms' primary and secondary metabolism. Among 20 P450s of the tuberculosis-causing Mycobacterium tuberculosis H37Rv, CYP128A1 is particularly important owing to its involvement in synthesizing electron transport molecules such as menaquinone-9 (MK9). This study employs different in silico approaches to understand CYP128 P450 family's distribution and structural aspects. Genome data-mining of 4250 mycobacterial species has revealed the presence of 2674 CYP128 P450s in 2646 mycobacterial species belonging to six different categories. Contrast features were observed in the CYP128 gene distribution, subfamily patterns, and characteristics of the secondary metabolite biosynthetic gene cluster (BGCs) between M. tuberculosis complex (MTBC) and other mycobacterial category species. In all MTBC species (except one) CYP128 P450s belong to subfamily A, whereas subfamily B is predominant in another four mycobacterial category species. Of CYP128 P450s, 78% was a part of BGCs with CYP124A1, or together with CYP124A1 and CYP121A1. The CYP128 family ranked fifth in the conservation ranking. Unique amino acid patterns are present at the EXXR and CXG motifs. Molecular dynamic simulation studies indicate that the CYP128A1 bind to MK9 with the highest affinity compared to the azole drugs analyzed. This study provides comprehensive comparative analysis and structural insights of CYP128A1 in M. tuberculosis.
Collapse
Affiliation(s)
- Nokwanda Samantha Ngcobo
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.S.N.); (Z.E.C.)
| | - Zinhle Edith Chiliza
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.S.N.); (Z.E.C.)
| | - Wanping Chen
- Department of Molecular Microbiology and Genetics, University of Göttingen, 37077 Göttingen, Germany;
| | - Jae-Hyuk Yu
- Department of Bacteriology, University of Wisconsin-Madison, 3155 MSB, 1550 Linden Drive, Madison, WI 53706, USA;
- Department of Systems Biotechnology, Konkuk University, Seoul 05029, Korea
| | - David R. Nelson
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA;
| | - Jack A. Tuszynski
- Department of Physics and Department of Oncology, University of Alberta, Edmonton, AB T6G 2E1, Canada;
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino TO, Italy
| | - Jordane Preto
- Université Claude Bernard Lyon 1, INSERM 1052, CNRS 5286, Centre Léon Bérard, Centre de Recherche en Cancérologie de Lyon, 69622 Lyon, France
| | - Khajamohiddin Syed
- Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Zululand, KwaDlangezwa 3886, South Africa; (N.S.N.); (Z.E.C.)
| |
Collapse
|
24
|
Johnston JM, Bulloch EM. Advances in menaquinone biosynthesis: sublocalisation and allosteric regulation. Curr Opin Struct Biol 2020; 65:33-41. [PMID: 32634692 DOI: 10.1016/j.sbi.2020.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/08/2020] [Accepted: 05/11/2020] [Indexed: 12/31/2022]
Abstract
Menaquinones (vitamin K2) are a family of redox-active small molecules with critical functions across all domains of life, including energy generation in bacteria and bone health in humans. The enzymes involved in menaquinone biosynthesis also have bioengineering applications and are potential antimicrobial drug targets. New insights into the essential roles of menaquinones, and their potential to cause redox-related toxicity, have highlighted the need for this pathway to be tightly controlled. Here, we provide an overview of our current understanding of the classical menaquinone biosynthesis pathway in bacteria. We also review recent discoveries on protein-level allostery and sublocalisation of membrane-bound enzymes that have provided insight into the regulation of flux through this biosynthetic pathway.
Collapse
Affiliation(s)
- Jodie M Johnston
- School of Physical and Chemical Sciences, Biomolecular Interaction Centre, and Maurice Wilkins Centre for MolecularBiodiscovery, University of Canterbury, Christchurch 8041, New Zealand.
| | - Esther Mm Bulloch
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for MolecularBiodiscovery, University of Auckland, Private Bag 92019, Auckland, New Zealand
| |
Collapse
|
25
|
Van Cleave C, Murakami HA, Samart N, Koehn JT, Maldonado P, Kreckel HD, Cope EJ, Basile A, Crick DC, Crans DC. Location of menaquinone and menaquinol headgroups in model membranes. CAN J CHEM 2020. [DOI: 10.1139/cjc-2020-0024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Menaquinones are lipoquinones that consist of a headgroup (naphthoquinone, menadione) and an isoprenyl sidechain. They function as electron transporters in prokaryotes such as Mycobacterium tuberculosis. For these studies, we used Langmuir monolayers and microemulsions to investigate how the menaquinone headgroup (menadione) and the menahydroquinone headgroup (menadiol) interact with model membrane interfaces to determine if differences are observed in the location of these headgroups in a membrane. It has been suggested that the differences in the locations are mainly caused by the isoprenyl sidechain rather than the headgroup quinone-to-quinol reduction during electron transport. This study presents evidence that suggests the influence of the headgroup drives the movement of the oxidized quinone and the reduced hydroquinone to different locations within the interface. Utilizing the model membranes of microemulsions and Langmuir monolayers, it is determined whether or not there is a difference in the location of menadione and menadiol within the interface. Based on our findings, we conclude that the menadione and menadiol may reside in different locations within model membranes. It follows that if menaquinone moves within the cell membrane upon menaquinol formation, it is due at least in part, to the differences in the properties of headgroup interactions with the membrane in addition to the isoprenyl sidechain.
Collapse
Affiliation(s)
- Cameron Van Cleave
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Heide A. Murakami
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Nuttaporn Samart
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
- Department of Chemistry, Rajabhat Rajanagarindra University, Chachoengsao, Thailand
| | - Jordan T. Koehn
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Pablo Maldonado
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Heidi D. Kreckel
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Elana J. Cope
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Andrea Basile
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
| | - Dean C. Crick
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA
| | - Debbie C. Crans
- Department of Chemistry, Colorado State University, Fort Collins, CO 80523, USA
- Cell and Molecular Biology Program, Colorado State University, Fort Collins, CO 80523, USA
| |
Collapse
|
26
|
Oxidative Phosphorylation—an Update on a New, Essential Target Space for Drug Discovery in Mycobacterium tuberculosis. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10072339] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
New drugs with new mechanisms of action are urgently required to tackle the global tuberculosis epidemic. Following the FDA-approval of the ATP synthase inhibitor bedaquiline (Sirturo®), energy metabolism has become the subject of intense focus as a novel pathway to exploit for tuberculosis drug development. This enthusiasm stems from the fact that oxidative phosphorylation (OxPhos) and the maintenance of the transmembrane electrochemical gradient are essential for the viability of replicating and non-replicating Mycobacterium tuberculosis (M. tb), the etiological agent of human tuberculosis (TB). Therefore, new drugs targeting this pathway have the potential to shorten TB treatment, which is one of the major goals of TB drug discovery. This review summarises the latest and key findings regarding the OxPhos pathway in M. tb and provides an overview of the inhibitors targeting various components. We also discuss the potential of new regimens containing these inhibitors, the flexibility of this pathway and, consequently, the complexity in targeting it. Lastly, we discuss opportunities and future directions of this drug target space.
Collapse
|
27
|
Nikitushkin VD, Trenkamp S, Demina GR, Shleeva MO, Kaprelyants AS. Metabolic profiling of dormant Mycolicibacterium smegmatis cells' reactivation reveals a gradual assembly of metabolic processes. Metabolomics 2020; 16:24. [PMID: 32025943 DOI: 10.1007/s11306-020-1645-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/22/2020] [Indexed: 01/24/2023]
Abstract
INTRODUCTION Under gradual acidification of the culture medium mycobacterial cells transit into a specific state characterized by low level of metabolic activity and morphological alterations. This state of non-replicative persistence (dormancy) is directly linked to physiological drug resistance, which complicates the efforts to eradicate the latent forms of TB. In order to find new anti-latent TB compounds, the metabolic processes which may occur in the state of dormancy and during the transition into the active state (reactivation) should be characterized. OBJECTIVES In the current study we analyzed the untargeted metabolomic profiles of dormant and reactivating Mycolicibacterium smegmatis cells (a model microorganism, bearing many common physiological traits of MTB), on the global scale level, since the characterization and analysis of the metabolites' dynamics would provide a comprehensive overview on global biochemical responses of the bacteria to stress conditions. METHODS The reactivation process was tracked by measuring the value of membrane potential, applying a ratio-metric approach, by the method of flow-cytometry. The crucial timepoints were selected and the bacteria were sampled to LC-MS metabolic profiling. RESULTS Reactivation of these cells after 60 days of storage revealed that this process proceeds in two stages: (I) a period, which lasts for 10 h and is characterized by a constant CFU number, unchangeable cell size, a minuscule increase of respiratory activity and a noticeable increase in membrane potential value, indicating the onset of the first metabolic processes during this time interval; the second phase (10-26 h) is characterized by acceleration of endogenous respiration, changes in the size of the cells and it finishes with the beginning of cells division. Analysis of the changes in the relative abundances of KEGG-annotated metabolites revealed that a significant number of metabolites, such as stearic acid, glycerol, D-glucose, trehalose-6-phosphate decrease their concentrations over the reactivation time, whereas in contrast, such metabolites as dodecanoic acid, mycobactin S, and other compounds of PG/AG biosynthesis are synthesized during reactivation. Differential analysis of metabolic profiles disclosed the activation of a number of metabolic pathways at the early reactivation stage: biosynthesis of secondary metabolites, purine and pyrimidine metabolism, glycerophospholipid and fatty acids metabolism etc. CONCLUSION: The data obtained indicate, despite the long-term storage of dormant cells in a state of minimal metabolic activity, according to metabolic profiling, they still retained a large number of metabolites. In the process of reactivation, the incremental stochastic assembly of the complete metabolic pathways occurs.
Collapse
Affiliation(s)
- Vadim D Nikitushkin
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071.
| | - Sandra Trenkamp
- Metabolomic Discoveries GmbH, Am Mühlenberg 11, 14476, Potsdam, Germany
| | - Galina R Demina
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
| | - Margarita O Shleeva
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
| | - Arseny S Kaprelyants
- A.N. Bach Institute of Biochemistry, Federal Research Centre "Fundamentals of Biotechnology" of the Russian Academy of Sciences, Leninsky Prospect 33, Build. 2, Moscow, Russia, 119071
| |
Collapse
|
28
|
Bashiri G, Nigon LV, Jirgis ENM, Ho NAT, Stanborough T, Dawes SS, Baker EN, Bulloch EMM, Johnston JM. Allosteric regulation of menaquinone (vitamin K 2) biosynthesis in the human pathogen Mycobacterium tuberculosis. J Biol Chem 2020; 295:3759-3770. [PMID: 32029475 DOI: 10.1074/jbc.ra119.012158] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/01/2020] [Indexed: 11/06/2022] Open
Abstract
Menaquinone (vitamin K2) plays a vital role in energy generation and environmental adaptation in many bacteria, including the human pathogen Mycobacterium tuberculosis (Mtb). Although menaquinone levels are known to be tightly linked to the cellular redox/energy status of the cell, the regulatory mechanisms underpinning this phenomenon are unclear. The first committed step in menaquinone biosynthesis is catalyzed by MenD, a thiamine diphosphate-dependent enzyme comprising three domains. Domains I and III form the MenD active site, but no function has yet been ascribed to domain II. Here, we show that the last cytosolic metabolite in the menaquinone biosynthesis pathway, 1,4-dihydroxy-2-naphthoic acid (DHNA), binds to domain II of Mtb-MenD and inhibits its activity. Using X-ray crystallography of four apo- and cofactor-bound Mtb-MenD structures, along with several spectroscopy assays, we identified three arginine residues (Arg-97, Arg-277, and Arg-303) that are important for both enzyme activity and the feedback inhibition by DHNA. Among these residues, Arg-277 appeared to be particularly important for signal propagation from the allosteric site to the active site. This is the first evidence of feedback regulation of the menaquinone biosynthesis pathway in bacteria, identifying a protein-level regulatory mechanism that controls menaquinone levels within the cell and may therefore represent a good target for disrupting menaquinone biosynthesis in M. tuberculosis.
Collapse
Affiliation(s)
- Ghader Bashiri
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Laura V Nigon
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Ehab N M Jirgis
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Ngoc Anh Thu Ho
- School of Physical and Chemical Sciences, Biomolecular Interaction Centre (BIC), and Maurice Wilkins Centre for Molecular Biodiscovery, University of Canterbury, Christchurch 8041, New Zealand
| | - Tamsyn Stanborough
- School of Physical and Chemical Sciences, Biomolecular Interaction Centre (BIC), and Maurice Wilkins Centre for Molecular Biodiscovery, University of Canterbury, Christchurch 8041, New Zealand
| | - Stephanie S Dawes
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Edward N Baker
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Esther M M Bulloch
- Laboratory of Structural Biology, School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Auckland 1010, New Zealand
| | - Jodie M Johnston
- School of Physical and Chemical Sciences, Biomolecular Interaction Centre (BIC), and Maurice Wilkins Centre for Molecular Biodiscovery, University of Canterbury, Christchurch 8041, New Zealand
| |
Collapse
|
29
|
Structure-function insights into elusive Mycobacterium tuberculosis protein Rv1916. Int J Biol Macromol 2019; 141:927-936. [PMID: 31505209 DOI: 10.1016/j.ijbiomac.2019.09.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 08/23/2019] [Accepted: 09/05/2019] [Indexed: 11/21/2022]
Abstract
Tuberculosis (TB) is one of the leading causes of death worldwide. Long duration of TB therapy, results in the persistence and development of drug resistant strains of causative organism Mycobacterium tuberculosis (Mtb). Novel drug targets against persistent Mtb is an immediate need for overcoming this global menace. Isocitrate lyase (ICL), the first enzyme of glyoxylate pathway, is essential for persistent Mtb and absent in humans, hence a propitious target for drug development. Pathogenic Mtb H37Rv, have two types of ICLs - ICL1 encoded by icl (Rv0467) is well characterized and homologous to eubacterial enzyme whereas ICL2 encoded by aceA is more related to eukaryotic isocitrate lyase. To compound it, the aceA gene is split into two ORFs namely rv1915/aceAa and rv1916/aceAb. No translational product has been reported for the later and therefore, in vivo existence of Rv1916/ICL2b is debatable. This study reports recombinant production of Rv1916 in heterologous host E. coli BL21 (DE3) for structure function studies. The studies categorically demonstrate that akin to Mtb ICL1, recombinant Rv1916 also possess dual ICL and methylisocitrate lyase (MICL) activities in vitro. Based on in silico analysis, a putative function linked to secondary metabolite synthesis is assigned to unique mycobacterial domain IV.
Collapse
|
30
|
Cordero PRF, Grinter R, Hards K, Cryle MJ, Warr CG, Cook GM, Greening C. Two uptake hydrogenases differentially interact with the aerobic respiratory chain during mycobacterial growth and persistence. J Biol Chem 2019; 294:18980-18991. [PMID: 31624148 DOI: 10.1074/jbc.ra119.011076] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/12/2019] [Indexed: 12/11/2022] Open
Abstract
To persist when nutrient sources are limited, aerobic soil bacteria metabolize atmospheric hydrogen (H2). This process is the primary sink in the global H2 cycle and supports the productivity of microbes in oligotrophic environments. H2-metabolizing bacteria possess [NiFe] hydrogenases that oxidize H2 to subatmospheric concentrations. The soil saprophyte Mycobacterium smegmatis has two such [NiFe] hydrogenases, designated Huc and Hhy, that belong to different phylogenetic subgroups. Both Huc and Hhy are oxygen-tolerant, oxidize H2 to subatmospheric concentrations, and enhance bacterial survival during hypoxia and carbon limitation. Why does M. smegmatis require two hydrogenases with a seemingly similar function? In this work, we resolved this question by showing that Huc and Hhy are differentially expressed, localized, and integrated into the respiratory chain. Huc is active in late exponential and early stationary phases, supporting energy conservation during mixotrophic growth and transition into dormancy. In contrast, Hhy is most active during long-term persistence, providing energy for maintenance processes following carbon exhaustion. We also show that Huc and Hhy are obligately linked to the aerobic respiratory chain via the menaquinone pool and are differentially affected by respiratory uncouplers. Consistently, these two enzymes interacted differentially with the respiratory terminal oxidases. Huc exclusively donated electrons to, and possibly physically associated with, the proton-pumping cytochrome bcc-aa 3 supercomplex. In contrast the more promiscuous Hhy also provided electrons to the cytochrome bd oxidase complex. These results indicate that, despite their similar characteristics, Huc and Hhy perform distinct functions during mycobacterial growth and survival.
Collapse
Affiliation(s)
- Paul R F Cordero
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Rhys Grinter
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Max J Cryle
- Monash Biomedicine Discovery Institute, Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Coral G Warr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia.,School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, OTA 9016, New Zealand
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| |
Collapse
|
31
|
Metabolite Profiling: A Tool for the Biochemical Characterisation of Mycobacterium sp. Microorganisms 2019; 7:microorganisms7050148. [PMID: 31130621 PMCID: PMC6560386 DOI: 10.3390/microorganisms7050148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/13/2019] [Accepted: 05/25/2019] [Indexed: 12/19/2022] Open
Abstract
Over the last decades, the prevalence of drug-resistance in Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, has increased. These findings have rekindled interest in elucidating the unique adaptive molecular and biochemistry physiology of Mycobacterium. The use of metabolite profiling independently or in combination with other levels of "-omic" analyses has proven an effective approach to elucidate key physiological/biochemical mechanisms associated with Mtb throughout infection. The following review discusses the use of metabolite profiling in the study of tuberculosis, future approaches, and the technical and logistical limitations of the methodology.
Collapse
|
32
|
Dhiman RK, Pujari V, Kincaid JM, Ikeh MA, Parish T, Crick DC. Characterization of MenA (isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate isoprenyltransferase) from Mycobacterium tuberculosis. PLoS One 2019; 14:e0214958. [PMID: 30978223 PMCID: PMC6461227 DOI: 10.1371/journal.pone.0214958] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 03/22/2019] [Indexed: 12/18/2022] Open
Abstract
The menaquinone biosynthetic pathway presents a promising drug target against Mycobacterium tuberculosis and potentially other Gram-positive pathogens. In the present study, the essentiality, steady state kinetics of MenA from M. tuberculosis and the mechanism of MenA inhibition by Ro 48-8071 were characterized. MenA [isoprenyl diphosphate:1,4-dihydroxy-2-naphthoate (DHNA) isoprenyltransferase] catalyzes a critical reaction in menaquinone biosynthesis that involves the conversion of cytosolic DHNA, to membrane bound demethylmenaquinone by transferring a hydrophobic 45-carbon isoprenoid chain (in the case of mycobacteria) to the ring nucleus of DHNA. Rv0534c previously identified as the gene encoding MenA in M. tuberculosis complemented a menA deletion in E. coli and an E. coli host expressing Rv0534c exhibited an eight-fold increase in MenA specific activity over the control strain harboring empty vector under similar assay conditions. Expression of Rv0534c is essential for mycobacterial survival and the native enzyme from M. tuberculosis H37Rv was characterized using membrane preparations as it was not possible to solubilize and purify the recombinant enzyme. The enzyme is absolutely dependent on the presence of a divalent cation for optimal activity with Mg+2 being the most effective and is active over a wide pH range, with pH 8.5 being optimal. The apparent Km values for DHNA and farnesyl diphosphate were found to be 8.2 and 4.3 μM, respectively. Ro 48-8071, a compound previously reported to inhibit mycobacterial MenA activity, is non-competitive with regard to DHNA and competitive with regard to the isoprenyldiphosphate substrate.
Collapse
Affiliation(s)
- Rakesh K. Dhiman
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Venugopal Pujari
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - James M. Kincaid
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Melanie A. Ikeh
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, United Kingdom
| | - Tanya Parish
- Queen Mary University of London, Barts & The London School of Medicine and Dentistry, London, United Kingdom
- TB Discovery Research, Infectious Disease Research Institute, Seattle, WA, United States of America
| | - Dean C. Crick
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| |
Collapse
|
33
|
Evans CE, Si Y, Matarlo JS, Yin Y, French JB, Tonge PJ, Tan DS. Structure-Based Design, Synthesis, and Biological Evaluation of Non-Acyl Sulfamate Inhibitors of the Adenylate-Forming Enzyme MenE. Biochemistry 2019; 58:1918-1930. [PMID: 30912442 PMCID: PMC6653581 DOI: 10.1021/acs.biochem.9b00003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
N-Acyl sulfamoyladenosines (acyl-AMS) have been used
extensively to inhibit adenylate-forming enzymes that are involved in a wide
range of biological processes. These acyl-AMS inhibitors are nonhydrolyzable
mimics of the cognate acyl adenylate intermediates that are bound tightly by
adenylate-forming enzymes. However, the anionic acyl sulfamate moiety presents a
pharmacological liability that may be detrimental to cell permeability and
pharmacokinetic profiles. We have previously developed the acyl sulfamate
OSB-AMS (1) as a potent inhibitor of the adenylate-forming enzyme
MenE, an o-succinylbenzoate-CoA (OSB-CoA) synthetase that is
required for bacterial menaquinone biosynthesis. Herein, we report the use of
computational docking to develop novel, non-acyl sulfamate inhibitors of MenE. A
m-phenyl ether-linked analogue (5) was found
to be the most potent inhibitor (IC50 = 8 μM;
Kd = 244 nM), and its X-ray co-crystal structure
was determined to characterize its binding mode in comparison to the
computational prediction. This work provides a framework for the development of
potent non-acyl sulfamate inhibitors of other adenylate-forming enzymes in the
future.
Collapse
|
34
|
Belete TM. Novel targets to develop new antibacterial agents and novel alternatives to antibacterial agents. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.humic.2019.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
35
|
Malwal SR, Chen L, Hicks H, Qu F, Liu W, Shillo A, Law WX, Zhang J, Chandnani N, Han X, Zheng Y, Chen CC, Guo RT, AbdelKhalek A, Seleem MN, Oldfield E. Discovery of Lipophilic Bisphosphonates That Target Bacterial Cell Wall and Quinone Biosynthesis. J Med Chem 2019; 62:2564-2581. [PMID: 30730737 DOI: 10.1021/acs.jmedchem.8b01878] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We report that alkyl-substituted bisphosphonates have activity against Bacillus anthracis Sterne (0.40 μg/mL), Mycobacterium smegmatis (1.4 μg/mL), Bacillus subtilis (1.0 μg/mL), and Staphylococcus aureus (13 μg/mL). In many cases, there is no effect of serum binding, as well as low activity against a human embryonic kidney cell line. Targeting of isoprenoid biosynthesis is involved with 74 having IC50 values of ∼100 nM against heptaprenyl diphosphate synthase and 200 nM against farnesyl diphosphate synthase. B. subtilis growth inhibition was rescued by addition of farnesyl diphosphate, menaquinone-4 (MK-4), or undecaprenyl phosphate (UP), and the combination of MK-4 and UP resulted in a 25× increase in ED50, indicating targeting of both quinone and cell wall biosynthesis. Clostridioides difficile was inhibited by 74, and since this organism does not synthesize quinones, cell wall biosynthesis is the likely target. We also solved three X-ray structures of inhibitors bound to octaprenyl diphosphate and/or undecaprenyl diphosphate synthases.
Collapse
Affiliation(s)
| | | | | | | | - Weidong Liu
- Industrial Enzymes National Engineering Laboratory , Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin 200208 , China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Engineering Research Center for Bio-enzyme Catalysis, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences , Hubei University , Wuhan 430062 , China
| | | | | | | | | | - Xu Han
- Industrial Enzymes National Engineering Laboratory , Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin 200208 , China
| | - Yingying Zheng
- Industrial Enzymes National Engineering Laboratory , Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin 200208 , China
| | - Chun-Chi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Engineering Research Center for Bio-enzyme Catalysis, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences , Hubei University , Wuhan 430062 , China
| | - Rey-Ting Guo
- Industrial Enzymes National Engineering Laboratory , Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences , Tianjin 200208 , China.,State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Collaborative Innovation Center for Green Transformation of Bio-resources, Hubei Engineering Research Center for Bio-enzyme Catalysis, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences , Hubei University , Wuhan 430062 , China
| | - Ahmed AbdelKhalek
- Department of Comparative Pathobiology, College of Veterinary Medicine , Purdue University , West Lafayette , Indiana 47907 , United States
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine , Purdue University , West Lafayette , Indiana 47907 , United States.,Purdue Institute of Inflammation, Immunology, and Infectious Disease , West Lafayette , Indiana 47907 , United States
| | | |
Collapse
|
36
|
2-aminoimidazoles collapse mycobacterial proton motive force and block the electron transport chain. Sci Rep 2019; 9:1513. [PMID: 30728417 PMCID: PMC6365497 DOI: 10.1038/s41598-018-38064-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/18/2018] [Indexed: 12/22/2022] Open
Abstract
There is an urgent need to develop new drugs against tuberculosis. In particular, it is critical to target drug tolerant Mycobacterium tuberculosis (M. tuberculosis), responsible, in part, for the lengthy antibiotic regimen required for treatment. We previously postulated that the presence of in vivo biofilm-like communities of M. tuberculosis could contribute to this drug tolerance. Consistent with this hypothesis, certain 2-aminoimidazole (2-AIs) molecules with anti-biofilm activity were shown to revert mycobacterial drug tolerance in an in vitro M. tuberculosis biofilm model. While exploring their mechanism of action, it was serendipitously observed that these 2-AI molecules also potentiated β-lactam antibiotics by affecting mycobacterial protein secretion and lipid export. As these two bacterial processes are energy-dependent, herein it was evaluated if 2-AI compounds affect mycobacterial bioenergetics. At low concentrations, 2B8, the lead 2-AI compound, collapsed both components of the proton motive force, similar to other cationic amphiphiles. Interestingly, however, the minimum inhibitory concentration of 2B8 against M. tuberculosis correlated with a higher drug concentration determined to interfere with the mycobacterial electron transport chain. Collectively, this study elucidates the mechanism of action of 2-AIs against M. tuberculosis, providing a tool to better understand mycobacterial bioenergetics and develop compounds with improved anti-mycobacterial activity.
Collapse
|
37
|
Puffal J, Mayfield JA, Moody DB, Morita YS. Demethylmenaquinone Methyl Transferase Is a Membrane Domain-Associated Protein Essential for Menaquinone Homeostasis in Mycobacterium smegmatis. Front Microbiol 2018; 9:3145. [PMID: 30619211 PMCID: PMC6305584 DOI: 10.3389/fmicb.2018.03145] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 12/04/2018] [Indexed: 12/20/2022] Open
Abstract
The intracellular membrane domain (IMD) in mycobacteria is a spatially distinct region of the plasma membrane with diverse functions. Previous comparative proteomic analysis of the IMD suggested that menaquinone biosynthetic enzymes are associated with this domain. In the present study, we determined the subcellular site of these enzymes using sucrose density gradient fractionation. We found that the last two enzymes, the methyltransferase MenG, and the reductase MenJ, are associated with the IMD in Mycobacterium smegmatis. MenA, the prenyltransferase that mediates the first membrane-associated step of the menaquinone biosynthesis, is associated with the conventional plasma membrane. For MenG, we additionally showed the polar enrichment of the fluorescent protein fusion colocalizing with an IMD marker protein in situ. To start dissecting the roles of IMD-associated enzymes, we further tested the physiological significance of MenG. The deletion of menG at the endogenous genomic loci was possible only when an extra copy of the gene was present, indicating that it is an essential gene in M. smegmatis. Using a tetracycline-inducible switch, we achieved gradual and partial depletion of MenG over three consecutive 24 h sub-cultures. This partial MenG depletion resulted in progressive slowing of growth, which corroborated the observation that menG is an essential gene. Upon MenG depletion, there was a significant accumulation of MenG substrate, demethylmenaquinone, even though the cellular level of menaquinone, the reaction product, was unaffected. Furthermore, the growth retardation was coincided with a lower oxygen consumption rate and ATP accumulation. These results imply a previously unappreciated role of MenG in regulating menaquinone homeostasis within the complex spatial organization of mycobacterial plasma membrane.
Collapse
Affiliation(s)
- Julia Puffal
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| | - Jacob A. Mayfield
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - D. Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Yasu S. Morita
- Department of Microbiology, University of Massachusetts, Amherst, MA, United States
| |
Collapse
|
38
|
Two active site arginines are critical determinants of substrate binding and catalysis in MenD: a thiamine-dependent enzyme in menaquinone biosynthesis. Biochem J 2018; 475:3651-3667. [DOI: 10.1042/bcj20180548] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/10/2018] [Accepted: 10/17/2018] [Indexed: 11/17/2022]
Abstract
The bacterial enzyme MenD, or 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase, catalyzes an essential Stetter reaction in menaquinone (vitamin K2) biosynthesis via thiamine diphosphate (ThDP)-bound tetrahedral post-decarboxylation intermediates. The detailed mechanism of this intermediate chemistry, however, is still poorly understood, but of significant interest given that menaquinone is an essential electron transporter in many pathogenic bacteria. Here, we used site-directed mutagenesis, enzyme kinetic assays, and protein crystallography to reveal an active–inactive intermediate equilibrium in MenD catalysis and its modulation by two conserved active site arginine residues. We observed that these conserved residues play a key role in shifting the equilibrium to the active intermediate by orienting the C2-succinyl group of the intermediates through strong ionic hydrogen bonding. We found that when this interaction is moderately weakened by amino acid substitutions, the resulting proteins are catalytically competent with the C2-succinyl group taking either the active or the inactive orientation in the post-decarboxylation intermediate. When this hydrogen-bonding interaction was strongly weakened, the succinyl group was re-oriented by 180° relative to the native intermediate, resulting in the reversal of the stereochemistry at the reaction center that disabled catalysis. Interestingly, this inactive intermediate was formed with a distinct kinetic behavior, likely as a result of a non-native mode of enzyme–substrate interaction. The mechanistic insights gained from these findings improve our understanding of the new ThDP-dependent catalysis. More importantly, the non-native-binding site of the inactive MenD intermediate uncovered here provides a new target for the development of antibiotics.
Collapse
|
39
|
Upadhyay A, Kumar S, Rooker SA, Koehn JT, Crans DC, McNeil MR, Lott JS, Crick DC. Mycobacterial MenJ: An Oxidoreductase Involved in Menaquinone Biosynthesis. ACS Chem Biol 2018; 13:2498-2507. [PMID: 30091899 DOI: 10.1021/acschembio.8b00402] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
MenJ, annotated as an oxidoreductase, was recently demonstrated to catalyze the reduction (saturation) of a single double bond in the isoprenyl side-chain of mycobacterial menaquinone. This modification was shown to be essential for bacterial survival in J774A.1 macrophage-like cells, suggesting that MenJ may be a conditional drug target in Mycobacterium tuberculosis and other pathogenic mycobacteria. Recombinant protein was expressed in a heterologous host, and the activity was characterized. Although highly regiospecific in vivo, the activity is not absolutely regiospecific in vitro; in addition, the enzyme is not specific for naphthoquinones vs benzoquinones. Coenzyme Q-1 (a benzoquinone, UQ-1) was used as the lipoquinone substrate, and NADH oxidation was followed spectrophotometrically as the activity readout. NADPH could not be substituted for NADH in the reaction mixture. The enzyme contains a FAD binding site that was 72% occupied in the purified recombinant protein. Enzyme activity was maximal at 37 °C and pH 7.0; addition of divalent cations, EDTA, and reducing agents such as dithiothreitol to the reaction mixture had no effect on activity. The addition of detergents did not stimulate activity, and addition of saturating levels of FAD had relatively little effect on the observed kinetic parameters. These properties allowed the development of a facile assay needed to study this potential drug target, which is also amenable to high throughput screening. The Km values for UQ-1 using recombinant MenJ from Mycobacterium smegmatis or M. tuberculosis without saturating concentrations of FAD were found to be 52 ± 9.6 and 44 ± 4.8 μM, respectively, while the KmNADH values were determined to be 59 ± 14 and 64 ± 15 μM. The Km for MK-1, the menaquinone analogue of UQ-1, using recombinant MenJ from M. tuberculosis without saturating concentrations of FAD but in the presence of 0.5% Tween 80 was shown to be 30 ± 2.9 μM. Thus, this is the first report of a kinetic characterization of a member of the geranylgeranyl reductase family of enzymes.
Collapse
Affiliation(s)
- Ashutosh Upadhyay
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Santosh Kumar
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Steven A. Rooker
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Jordan T. Koehn
- Chemistry Department, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Debbie C. Crans
- Chemistry Department, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Michael R. McNeil
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| | - J. Shaun Lott
- Biological Sciences, The University of Auckland, Auckland 1010, New Zealand
| | - Dean C. Crick
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, United States
| |
Collapse
|
40
|
Qin M, Song H, Dai X, Chan C, Chan W, Guo Z. Single‐Turnover Kinetics Reveal a Distinct Mode of Thiamine Diphosphate‐Dependent Catalysis in Vitamin K Biosynthesis. Chembiochem 2018; 19:1514-1522. [DOI: 10.1002/cbic.201800143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Mingming Qin
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Haigang Song
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Present address: Division of Structural BiologyWellcome Trust Centre of Human GenomicsUniversity of Oxford Roosevelt Drive Oxford OX3 7BN UK
| | - Xin Dai
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Chi‐Kong Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Wan Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Zhihong Guo
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| |
Collapse
|
41
|
Passi A, Rajput NK, Wild DJ, Bhardwaj A. RepTB: a gene ontology based drug repurposing approach for tuberculosis. J Cheminform 2018; 10:24. [PMID: 29785561 PMCID: PMC5962481 DOI: 10.1186/s13321-018-0276-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/23/2018] [Indexed: 11/12/2022] Open
Abstract
Tuberculosis (TB) is the world’s leading infectious killer with 1.8 million deaths in 2015 as reported by WHO. It is therefore imperative that alternate routes of identification of novel anti-TB compounds are explored given the time and costs involved in new drug discovery process. Towards this, we have developed RepTB. This is a unique drug repurposing approach for TB that uses molecular function correlations among known drug-target pairs to predict novel drug-target interactions. In this study, we have created a Gene Ontology based network containing 26,404 edges, 6630 drug and 4083 target nodes. The network, enriched with molecular function ontology, was analyzed using Network Based Inference (NBI). The association scores computed from NBI are used to identify novel drug-target interactions. These interactions are further evaluated based on a combined evidence approach for identification of potential drug repurposing candidates. In this approach, targets which have no known variation in clinical isolates, no human homologs, and are essential for Mtb’s survival and or virulence are prioritized. We analyzed predicted DTIs to identify target pairs whose predicted drugs may have synergistic bactericidal effect. From the list of predicted DTIs from RepTB, four TB targets, namely, FolP1 (Dihydropteroate synthase), Tmk (Thymidylate kinase), Dut (Deoxyuridine 5′-triphosphate nucleotidohydrolase) and MenB (1,4-dihydroxy-2-naphthoyl-CoA synthase) may be selected for further validation. In addition, we observed that in some cases there is significant chemical structure similarity between predicted and reported drugs of prioritized targets, lending credence to our approach. We also report new chemical space for prioritized targets that may be tested further. We believe that with increasing drug-target interaction dataset RepTB will be able to offer better predictive value and is amenable for identification of drug-repurposing candidates for other disease indications too.
Collapse
Affiliation(s)
- Anurag Passi
- Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, 160036, India.,Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai, Tamil Nadu, 600113, India
| | - Neeraj Kumar Rajput
- Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, 160036, India
| | - David J Wild
- School of Informatics, Computing, and Engineering, Indiana University, Bloomington, IN, 47405, USA.
| | - Anshu Bhardwaj
- Bioinformatics Centre, Institute of Microbial Technology, Council of Scientific and Industrial Research, Chandigarh, 160036, India. .,Academy of Scientific and Innovative Research, Council of Scientific and Industrial Research, Training and Development Complex, CSIR Campus, CSIR Road, Taramani, Chennai, Tamil Nadu, 600113, India.
| |
Collapse
|
42
|
Baek I, Kim M, Lee I, Na SI, Goodfellow M, Chun J. Phylogeny Trumps Chemotaxonomy: A Case Study Involving Turicella otitidis. Front Microbiol 2018; 9:834. [PMID: 29760685 PMCID: PMC5936774 DOI: 10.3389/fmicb.2018.00834] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/12/2018] [Indexed: 11/13/2022] Open
Abstract
The genus Turicella was proposed to harbor clinical strains isolated from middle-ear fluids of patients with otitis media. 16S rRNA phylogeny showed that it belonged to the mycolic acid-containing actinobacteria, currently classified in the order Corynebacteriales, and was closely related to the genus Corynebacterium. A new genus was proposed for the organisms as unlike corynebacteria they lacked mycolic acids and had different menaquinones. Here, we carried out large-scale comparative genomics on representative strains of the genera Corynebacterium and Turicella to check if this chemotaxonomic classification is justified. Three genes that are known to play an essential role in mycolic acid biosynthesis were absent in Turicella and two other mycolate-less Corynebacterium spp., explaining the lack of mycolic acids resulted from the deletion of genes and does not confer any phylogenetic context. Polyphasic phylogenetic analyses using 16S rRNA, bacterial core genes and genes responsible for synthesizing menaquinones unequivocally indicate that Turicella is a true member of the genus Corynebacterium. Here, we demonstrate that menaquinone and mycolic acid that have been used as critical taxonomic markers should be interpreted carefully, particularly when genome-based taxonomy is readily available. Based on the phylogenetic analysis, we propose to reclassify Turicella otitidis as Corynebacterium otitidis comb. nov.
Collapse
Affiliation(s)
- Inwoo Baek
- School of Biological Sciences, Seoul National University, Seoul, South Korea.,Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Mincheol Kim
- Division of Polar Life Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Imchang Lee
- School of Biological Sciences, Seoul National University, Seoul, South Korea.,Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Seong-In Na
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea.,Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| | - Michael Goodfellow
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Jongsik Chun
- School of Biological Sciences, Seoul National University, Seoul, South Korea.,Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea.,Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul, South Korea
| |
Collapse
|
43
|
Iqbal IK, Bajeli S, Akela AK, Kumar A. Bioenergetics of Mycobacterium: An Emerging Landscape for Drug Discovery. Pathogens 2018; 7:E24. [PMID: 29473841 PMCID: PMC5874750 DOI: 10.3390/pathogens7010024] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 01/29/2018] [Accepted: 01/31/2018] [Indexed: 11/16/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) exhibits remarkable metabolic flexibility that enables it to survive a plethora of host environments during its life cycle. With the advent of bedaquiline for treatment of multidrug-resistant tuberculosis, oxidative phosphorylation has been validated as an important target and a vulnerable component of mycobacterial metabolism. Exploiting the dependence of Mtb on oxidative phosphorylation for energy production, several components of this pathway have been targeted for the development of new antimycobacterial agents. This includes targeting NADH dehydrogenase by phenothiazine derivatives, menaquinone biosynthesis by DG70 and other compounds, terminal oxidase by imidazopyridine amides and ATP synthase by diarylquinolines. Importantly, oxidative phosphorylation also plays a critical role in the survival of persisters. Thus, inhibitors of oxidative phosphorylation can synergize with frontline TB drugs to shorten the course of treatment. In this review, we discuss the oxidative phosphorylation pathway and development of its inhibitors in detail.
Collapse
Affiliation(s)
- Iram Khan Iqbal
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Sapna Bajeli
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Ajit Kumar Akela
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| | - Ashwani Kumar
- Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh 160036, India.
| |
Collapse
|
44
|
Hards K, Cook GM. Targeting bacterial energetics to produce new antimicrobials. Drug Resist Updat 2018; 36:1-12. [DOI: 10.1016/j.drup.2017.11.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/25/2017] [Accepted: 10/31/2017] [Indexed: 12/31/2022]
|
45
|
Oxidative Phosphorylation as a Target Space for Tuberculosis: Success, Caution, and Future Directions. Microbiol Spectr 2017; 5. [PMID: 28597820 DOI: 10.1128/microbiolspec.tbtb2-0014-2016] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The emergence and spread of drug-resistant pathogens, and our inability to develop new antimicrobials to combat resistance, have inspired scientists to seek out new targets for drug development. The Mycobacterium tuberculosis complex is a group of obligately aerobic bacteria that have specialized for inhabiting a wide range of intracellular and extracellular environments. Two fundamental features in this adaptation are the flexible utilization of energy sources and continued metabolism in the absence of growth. M. tuberculosis is an obligately aerobic heterotroph that depends on oxidative phosphorylation for growth and survival. However, several studies are redefining the metabolic breadth of the genus. Alternative electron donors and acceptors may provide the maintenance energy for the pathogen to maintain viability in hypoxic, nonreplicating states relevant to latent infection. This hidden metabolic flexibility may ultimately decrease the efficacy of drugs targeted against primary dehydrogenases and terminal oxidases. However, it may also open up opportunities to develop novel antimycobacterials targeting persister cells. In this review, we discuss the progress in understanding the role of energetic targets in mycobacterial physiology and pathogenesis and the opportunities for drug discovery.
Collapse
|
46
|
Gupta VK, Kumar MM, Singh D, Bisht D, Sharma S. Drug targets in dormant Mycobacterium tuberculosis: can the conquest against tuberculosis become a reality? Infect Dis (Lond) 2017; 50:81-94. [DOI: 10.1080/23744235.2017.1377346] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Vivek Kumar Gupta
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, India
| | - M. Madhan Kumar
- Department of Immunology, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, India
| | - Dharmendra Singh
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, India
| | - Deepa Bisht
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, India
| | - Shweta Sharma
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases (ICMR), Agra, India
| |
Collapse
|
47
|
Ceniceros A, Dijkhuizen L, Petrusma M, Medema MH. Genome-based exploration of the specialized metabolic capacities of the genus Rhodococcus. BMC Genomics 2017; 18:593. [PMID: 28793878 PMCID: PMC5550956 DOI: 10.1186/s12864-017-3966-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/27/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Bacteria of the genus Rhodococcus are well known for their ability to degrade a large range of organic compounds. Some rhodococci are free-living, saprophytic bacteria; others are animal and plant pathogens. Recently, several studies have shown that their genomes encode putative pathways for the synthesis of a large number of specialized metabolites that are likely to be involved in microbe-microbe and host-microbe interactions. To systematically explore the specialized metabolic potential of this genus, we here performed a comprehensive analysis of the biosynthetic coding capacity across publicly available rhododoccal genomes, and compared these with those of several Mycobacterium strains as well as that of their mutual close relative Amycolicicoccus subflavus. RESULTS Comparative genomic analysis shows that most predicted biosynthetic gene cluster families in these strains are clade-specific and lack any homology with gene clusters encoding the production of known natural products. Interestingly, many of these clusters appear to encode the biosynthesis of lipopeptides, which may play key roles in the diverse environments were rhodococci thrive, by acting as biosurfactants, pathogenicity factors or antimicrobials. We also identified several gene cluster families that are universally shared among all three genera, which therefore may have a more 'primary' role in their physiology. Inactivation of these clusters by mutagenesis might help to generate weaker strains that can be used as live vaccines. CONCLUSIONS The genus Rhodococcus thus provides an interesting target for natural product discovery, in view of its large and mostly uncharacterized biosynthetic repertoire, its relatively fast growth and the availability of effective genetic tools for its genomic modification.
Collapse
Affiliation(s)
- Ana Ceniceros
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747, AG, Groningen, The Netherlands
| | - Lubbert Dijkhuizen
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747, AG, Groningen, The Netherlands.
| | - Mirjan Petrusma
- Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Nijenborgh 7, 9747, AG, Groningen, The Netherlands
| | - Marnix H Medema
- Bioinformatics Group, Wageningen University, Droevendaalsesteeg 1, 6708, PB, Wageningen, The Netherlands.
| |
Collapse
|
48
|
Electron Transport Chain Is Biochemically Linked to Pilus Assembly Required for Polymicrobial Interactions and Biofilm Formation in the Gram-Positive Actinobacterium Actinomyces oris. mBio 2017. [PMID: 28634238 PMCID: PMC5478893 DOI: 10.1128/mbio.00399-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Gram-positive actinobacteria Actinomyces spp. are key colonizers in the development of oral biofilms due to the inherent ability of Actinomyces to adhere to receptor polysaccharides on the surface of oral streptococci and host cells. This receptor-dependent bacterial interaction, or coaggregation, requires a unique sortase-catalyzed pilus consisting of the pilus shaft FimA and the coaggregation factor CafA forming the pilus tip. While the essential role of the sortase machine SrtC2 in pilus assembly, biofilm formation, and coaggregation has been established, little is known about trans-acting factors contributing to these processes. We report here a large-scale Tn5 transposon screen for mutants defective in Actinomyces oris coaggregation with Streptococcus oralis. We obtained 33 independent clones, 13 of which completely failed to aggregate with S. oralis, and the remainder of which exhibited a range of phenotypes from severely to weakly defective coaggregation. The former had Tn5 insertions in fimA, cafA, or srtC2, as expected; the latter were mapped to genes coding for uncharacterized proteins and various nuo genes encoding the NADH dehydrogenase subunits. Electron microscopy and biochemical analyses of mutants with nonpolar deletions of nuo genes and ubiE, a menaquinone C-methyltransferase-encoding gene downstream of the nuo locus, confirmed the pilus and coaggregation defects. Both nuoA and ubiE mutants were defective in oxidation of MdbA, the major oxidoreductase required for oxidative folding of pilus proteins. Furthermore, supplementation of the ubiE mutant with exogenous menaquinone-4 rescued the cell growth and pilus defects. Altogether, we propose that the A. oris electron transport chain is biochemically linked to pilus assembly via oxidative protein folding. The Gram-positive actinobacterium A. oris expresses adhesive pili, or fimbriae, that are essential to biofilm formation and Actinomyces interactions with other bacteria, termed coaggregation. While the critical role of the conserved sortase machine in pilus assembly and the disulfide bond-forming catalyst MdbA in oxidative folding of pilins has been established, little is known about other trans-acting factors involved in these processes. Using a Tn5 transposon screen for mutants defective in coaggregation with Streptococcus oralis, we found that genetic disruption of the NADH dehydrogenase and menaquinone biosynthesis detrimentally alters pilus assembly. Further biochemical characterizations determined that menaquinone is important for reactivation of MdbA. This study supports the notion that the electron transport chain is biochemically linked to pilus assembly in A. oris via oxidative folding of pilin precursors.
Collapse
|
49
|
Chen Y, Li TL, Lin X, Li X, Li XD, Guo Z. Crystal structure of the thioesterification conformation of Bacillus subtilis o-succinylbenzoyl-CoA synthetase reveals a distinct substrate-binding mode. J Biol Chem 2017; 292:12296-12310. [PMID: 28559280 DOI: 10.1074/jbc.m117.790410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/25/2017] [Indexed: 02/03/2023] Open
Abstract
o-Succinylbenzoyl-CoA (OSB-CoA) synthetase (MenE) is an essential enzyme in bacterial vitamin K biosynthesis and an important target in the development of new antibiotics. It is a member of the adenylating enzymes (ANL) family, which reconfigure their active site in two different active conformations, one for the adenylation half-reaction and the other for a thioesterification half-reaction, in a domain-alternation catalytic mechanism. Although several aspects of the adenylating mechanism in MenE have recently been uncovered, its thioesterification conformation remains elusive. Here, using a catalytically competent Bacillus subtilis mutant protein complexed with an OSB-CoA analogue, we determined MenE high-resolution structures to 1.76 and 1.90 Å resolution in a thioester-forming conformation. By comparison with the adenylation conformation, we found that MenE's C-domain rotates around the Ser-384 hinge by 139.5° during domain-alternation catalysis. The structures also revealed a thioesterification active site specifically conserved among MenE orthologues and a substrate-binding mode distinct from those of many other acyl/aryl-CoA synthetases. Of note, using site-directed mutagenesis, we identified several residues that specifically contribute to the thioesterification half-reaction without affecting the adenylation half-reaction. Moreover, we observed a substantial movement of the activated succinyl group in the thioesterification half-reaction. These findings provide new insights into the domain-alternation catalysis of a bacterial enzyme essential for vitamin K biosynthesis and of its adenylating homologues in the ANL enzyme family.
Collapse
Affiliation(s)
- Yaozong Chen
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Tin Lok Li
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Xingbang Lin
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Xin Li
- Department of Chemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Xiang David Li
- Department of Chemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Zhihong Guo
- Department of Chemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
| |
Collapse
|
50
|
A Novel Small-Molecule Inhibitor of the Mycobacterium tuberculosis Demethylmenaquinone Methyltransferase MenG Is Bactericidal to Both Growing and Nutritionally Deprived Persister Cells. mBio 2017; 8:mBio.02022-16. [PMID: 28196957 PMCID: PMC5312080 DOI: 10.1128/mbio.02022-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Active tuberculosis (TB) and latent Mycobacterium tuberculosis infection both require lengthy treatments to achieve durable cures. This problem has partly been attributable to the existence of nonreplicating M. tuberculosis “persisters” that are difficult to kill using conventional anti-TB treatments. Compounds that target the respiratory pathway have the potential to kill both replicating and persistent M. tuberculosis and shorten TB treatment, as this pathway is essential in both metabolic states. We developed a novel respiratory pathway-specific whole-cell screen to identify new respiration inhibitors. This screen identified the biphenyl amide GSK1733953A (DG70) as a likely respiration inhibitor. DG70 inhibited both clinical drug-susceptible and drug-resistant M. tuberculosis strains. Whole-genome sequencing of DG70-resistant colonies identified mutations in menG (rv0558), which is responsible for the final step in menaquinone biosynthesis and required for respiration. Overexpression of menG from wild-type and DG70-resistant isolates increased the DG70 MIC by 4× and 8× to 30×, respectively. Radiolabeling and high-resolution mass spectrometry studies confirmed that DG70 inhibited the final step in menaquinone biosynthesis. DG70 also inhibited oxygen utilization and ATP biosynthesis, which was reversed by external menaquinone supplementation. DG70 was bactericidal in actively replicating cultures and in a nutritionally deprived persistence model. DG70 was synergistic with the first-line TB drugs isoniazid, rifampin, and the respiratory inhibitor bedaquiline. The combination of DG70 and isoniazid completely sterilized cultures in the persistence model by day 10. These results suggest that MenG is a good therapeutic target and that compounds targeting MenG along with standard TB therapy have the potential to shorten TB treatment duration. This study shows that MenG, which is responsible for the last enzymatic step in menaquinone biosynthesis, may be a good drug target for improving TB treatments. We describe the first small-molecule inhibitor (DG70) of Mycobacterium tuberculosis MenG and show that DG70 has characteristics that are highly desirable for a new antitubercular agent, including bactericidality against both actively growing and nonreplicating mycobacteria and synergy with several first-line drugs that are currently used to treat TB.
Collapse
|