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Harrison GA, Wang ER, Cho K, Mreyoud Y, Sarkar S, Almqvist F, Patti GJ, Stallings CL. Inducing vulnerability to InhA inhibition restores isoniazid susceptibility in drug-resistant Mycobacterium tuberculosis. mBio 2024; 15:e0296823. [PMID: 38294237 PMCID: PMC10936210 DOI: 10.1128/mbio.02968-23] [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: 11/13/2023] [Accepted: 12/20/2023] [Indexed: 02/01/2024] Open
Abstract
Of the approximately 10 million cases of Mycobacterium tuberculosis (Mtb) infections each year, over 10% are resistant to the frontline antibiotic isoniazid (INH). INH resistance is predominantly caused by mutations that decrease the activity of the bacterial enzyme KatG, which mediates the conversion of the pro-drug INH to its active form INH-NAD. We previously discovered an inhibitor of Mtb respiration, C10, that enhances the bactericidal activity of INH, prevents the emergence of INH-resistant mutants, and re-sensitizes a collection of INH-resistant mutants to INH through an unknown mechanism. To investigate the mechanism of action of C10, we exploited the toxicity of high concentrations of C10 to select for resistant mutants. We discovered two mutations that confer resistance to the disruption of energy metabolism and allow for the growth of Mtb in high C10 concentrations, indicating that growth inhibition by C10 is associated with inhibition of respiration. Using these mutants as well as direct inhibitors of the Mtb electron transport chain, we provide evidence that inhibition of energy metabolism by C10 is neither sufficient nor necessary to potentiate killing by INH. Instead, we find that C10 acts downstream of INH-NAD synthesis, causing Mtb to become particularly sensitive to inhibition of the INH-NAD target, InhA, without changing the concentration of INH-NAD or the activity of InhA, the two predominant mechanisms of potentiating INH. Our studies revealed that there exists a vulnerability in Mtb that can be exploited to render Mtb sensitive to otherwise subinhibitory concentrations of InhA inhibitor.IMPORTANCEIsoniazid (INH) is a critical frontline antibiotic to treat Mycobacterium tuberculosis (Mtb) infections. INH efficacy is limited by its suboptimal penetration of the Mtb-containing lesion and by the prevalence of clinical INH resistance. We previously discovered a compound, C10, that enhances the bactericidal activity of INH, prevents the emergence of INH-resistant mutants, and re-sensitizes a set of INH-resistant mutants to INH. Resistance is typically mediated by katG mutations that decrease the activation of INH, which is required for INH to inhibit the essential enzyme InhA. Our current work demonstrates that C10 re-sensitizes INH-resistant katG-hypomorphs without enhancing the activation of INH. We furthermore show that C10 causes Mtb to become particularly vulnerable to InhA inhibition without compromising InhA activity on its own. Therefore, C10 represents a novel strategy to curtail the development of INH resistance and to sensitize Mtb to sub-lethal doses of INH, such as those achieved at the infection site.
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Affiliation(s)
- Gregory A. Harrison
- Department of Molecular Microbiology, Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Erin R. Wang
- Department of Molecular Microbiology, Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kevin Cho
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Yassin Mreyoud
- Department of Molecular Microbiology, Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Souvik Sarkar
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Fredrik Almqvist
- Department of Chemistry, Umeå University, Umeå, Sweden
- Umeå Centre for Microbial Research, UCMR, Umeå University, Umeå, Sweden
| | - Gary J. Patti
- Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri, USA
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Metabolomics and Isotope Tracing, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Christina L. Stallings
- Department of Molecular Microbiology, Center for Women’s Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri, USA
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Onyenaka C, Idowu KA, Ha NP, Graviss EA, Olaleye OA. Anti-Tuberculosis Potential of OJT008 against Active and Multi-Drug-Resistant Mycobacterium Tuberculosis: In Silico and In Vitro Inhibition of Methionine Aminopeptidase. Int J Mol Sci 2023; 24:17142. [PMID: 38138972 PMCID: PMC10742973 DOI: 10.3390/ijms242417142] [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: 09/21/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023] Open
Abstract
Despite the recent progress in the diagnosis of tuberculosis (TB), the chemotherapeutic management of TB continues to be challenging. Mycobacterium tuberculosis (Mtb), the etiological agent of TB, is classified as the 13th leading cause of death globally. In addition, 450,000 people were reported to develop multi-drug-resistant TB globally. The current project focuses on targeting methionine aminopeptidase (MetAP), an essential protein for the viability of Mtb. MetAP is a metalloprotease that catalyzes the excision of the N-terminal methionine (NME) during protein synthesis, allowing the enzyme to be an auspicious target for the development of novel therapeutic agents for the treatment of TB. Mtb possesses two MetAP1 isoforms, MtMetAP1a and MtMetAP1c, which are vital for Mtb viability and, hence, a promising chemotherapeutic target for Mtb therapy. In this study, we cloned and overexpressed recombinant MtMetAP1c. We investigated the in vitro inhibitory effect of the novel MetAP inhibitor, OJT008, on the cobalt ion- and nickel ion-activated MtMetAP1c, and the mechanism of action was elucidated through an in silico approach. The compound's potency against replicating and multi-drug-resistant (MDR) Mtb strains was also investigated. The induction of the overexpressed recombinant MtMetAP1c was optimized at 8 h with a final concentration of 1 mM Isopropyl β-D-1-thiogalactopyranoside. The average yield from 1 L of Escherichia coli culture for MtMetAP1c was 4.65 mg. A preliminary MtMetAP1c metal dependency screen showed optimum activation with nickel and cobalt ions occurred at 100 µM. The half-maximal inhibitory concentration (IC50) values of OJT008 against MtMetAP1c activated with CoCl2 and NiCl2 were 11 µM and 40 µM, respectively. The in silico study showed OJT008 strongly binds to both metal-activated MtMetAP1c, as evidenced by strong molecular interactions and a higher binding score, thereby corroborating our result. This in silico study validated the pharmacophore's metal specificity. The potency of OJT008 against both active and MDR Mtb was <0.063 µg/mL. Our study reports OJT008 as an inhibitor of MtMetAP1c, which is potent at low micromolar concentrations against both active susceptible and MDR Mtb. These results suggest OJT008 is a potential lead compound for the development of novel small molecules for the therapeutic management of TB.
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Affiliation(s)
- Collins Onyenaka
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA (K.A.I.)
| | - Kehinde A. Idowu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA (K.A.I.)
| | - Ngan P. Ha
- Center for Infectious Disease Research, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Edward A. Graviss
- Center for Infectious Disease Research, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Omonike A. Olaleye
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA (K.A.I.)
- Center for Infectious Disease Research, Houston Methodist Research Institute, Houston, TX 77030, USA
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From bitter to delicious: properties and uses of microbial aminopeptidases. World J Microbiol Biotechnol 2023; 39:72. [PMID: 36625962 DOI: 10.1007/s11274-022-03501-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 12/14/2022] [Indexed: 01/11/2023]
Abstract
Protein hydrolysates are easily digested and utilized by humans and animals, and are less likely to cause allergies. Protein hydrolysis caused by endopeptidases often leads to the exposure of hydrophobic amino acids at the ends of peptides, which consequently causes bitter taste. Microbial aminopeptidases remove the exposed hydrophobic amino acids at the ends of aminopeptides, which improves taste, allowing for easier production. This processe is attacking significant attention from industry and laboratories. Aminopeptidases selectively hydrolyze peptide bonds from the N-terminal of proteins or peptides to produce free amino acids. Aminopeptidases can be classified into leucine, lysine, methionine and proline aminopeptidases by hydrolyzed N-terminal residues; metallo-, serine- and cysteine- aminopeptidases by the reaction mechanisms; dipeptide and triphoptide enzymes by the released number of amino acid residues at the end of hydrolyzed peptides; or acidic, neutral and basic aminopeptidases by their optimal hydrolysis pH. Commercial aminopeptidases are generally produced by microbial fermentation, and are mainly applied in the debittering of protein hydrolysates, the deep hydrolysis of protein, and the production of condiments, cheese, and bioactive peptides, as well as for disease detection in the medical industry.
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Juhás M, Pallabothula VSK, Grabrijan K, Šimovičová M, Janďourek O, Konečná K, Bárta P, Paterová P, Gobec S, Sosič I, Zitko J. Design, synthesis and biological evaluation of substituted 3-amino-N-(thiazol-2-yl)pyrazine-2-carboxamides as inhibitors of mycobacterial methionine aminopeptidase 1. Bioorg Chem 2021; 118:105489. [PMID: 34826708 DOI: 10.1016/j.bioorg.2021.105489] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 11/02/2021] [Accepted: 11/10/2021] [Indexed: 11/18/2022]
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) is the number one cause of deaths due to a single infectious agent worldwide. The treatment of TB is lengthy and often complicated by the increasing drug resistance. New compounds with new mechanisms of action are therefore needed. We present the design, synthesis, and biological evaluation of pyrazine-based inhibitors of a prominent antimycobacterial drug target - mycobacterial methionine aminopeptidase 1 (MtMetAP1). The inhibitory activities of the presented compounds were evaluated against the MtMetAP1a isoform, and all derivatives were tested against a broad spectrum of myco(bacteria) and fungi. The cytotoxicity of the compounds was also investigated using Hep G2 cell lines. Overall, high inhibition of the isolated enzyme was observed for 3-substituted N-(thiazol-2-yl)pyrazine-2-carboxamides, particularly when the substituent was represented by 2-substituted benzamide. The extent of inhibition was strongly dependent on the used metal cofactor. The highest inhibition was seen in the presence of Ni2+. Several compounds also showed mediocre in vitro potency against Mtb (both Mtb H37Ra and H37Rv). Despite the structural similarities of bacterial and fungal MetAP1 to mycobacterial MtMetAP1, title compounds did not exert antibacterial nor antifungal activity. The reasons behind the higher activity of 2-substituted benzamido derivatives, as well as the correlation of enzyme inhibition with the in vitro growth inhibition activity is discussed.
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Affiliation(s)
- Martin Juhás
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Vinod S K Pallabothula
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Katarina Grabrijan
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia.
| | - Martina Šimovičová
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Ondřej Janďourek
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Klára Konečná
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Pavel Bárta
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
| | - Pavla Paterová
- University Hospital Hradec Králové, Department of Clinical Microbiology, Sokolská 581, 500 05 Hradec Králové, Czech Republic.
| | - Stanislav Gobec
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia.
| | - Izidor Sosič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, SI-1000 Ljubljana, Slovenia.
| | - Jan Zitko
- Charles University, Faculty of Pharmacy in Hradec Králové, Akademika Heyrovského 1203, 500 05 Hradec Králové, Czech Republic.
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Guo C, Xiao Y, Bi F, Lin W, Wang H, Yao, H, Lin D. Recombinant expression, biophysical and functional characterization of ClpS from Mycobacterium tuberculosis. Acta Biochim Biophys Sin (Shanghai) 2019; 51:1158-1167. [PMID: 31650179 DOI: 10.1093/abbs/gmz102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Indexed: 11/13/2022] Open
Abstract
Intracellular proteolysis is attracting more and more attention for its unique and important character in Mycobacterium tuberculosis (Mt). The ClpS protein from Mt (MtClpS) plays a critical role in intracellular proteolysis by recognizing N-end rule substrates, which makes it become a potential target for antibacterial drugs. However, the molecular mechanism of MtClpS recognizing N-end rule substrates remains unclear. Preparation of highly concentrated and pure MtClpS protein is a prerequisite for further structural and functional studies. In the present work, we tried several fusion tags and various expression conditions to maximize the production of MtClpS in Escherichia coli. We established an efficient approach for preparing the MtClpS protein with a high yield of 24.7 mg/l and a high purity of 98%. After buffer screening, we obtained a stable MtClpS protein sample concentrated at 0.63 mM in the presence of glycerol, l-Arginine, and l-Glutamate. Moreover, circular dichroism characterization indicated that the secondary structure of MtClpS consists of 38% α-helix and 24% β-sheet. The 2D 1H-15N HSQC nuclear magnetic resonance spectrum showed a good dispersion of resonance peaks with uniform intensity, indicating that the purified MtClpS protein was well folded and conformationally homogeneous. Isothermal titration calorimetry experiments revealed significant interactions of MtClpS with N-end rule peptides beginning with Leu, Tyr, Trp, or Phe. Furthermore, residues D34, D35, and H66 were confirmed as key residues for MtClpS recognizing the N-end rule peptide. The successful expression and biophysical characterization of MtClpS enabled us to gain insight into the molecular mechanism of MtClpS recognizing N-end rule substrates. The obtained stable and pure recombinant MtClpS will enable future inhibitor screening experiments.
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Affiliation(s)
- Chenyun Guo
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Yihang Xiao
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Fangkai Bi
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Weiliang Lin
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Huilin Wang
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Hongwei Yao,
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Donghai Lin
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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Naor N, Gadot O, Meir M, Barkan D. Peptide Deformylase (def) is essential in Mycobacterium smegmatis, but the essentiality is compensated by inactivation of methionine formylation. BMC Microbiol 2019; 19:232. [PMID: 31655553 PMCID: PMC6815462 DOI: 10.1186/s12866-019-1611-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 10/06/2019] [Indexed: 11/10/2022] Open
Abstract
Background Co-translational processes in bacteria are attractive drug targets, but while some processes are essential, others are not. The essentiality of Peptide Deformylase (PDF, def) for vitality of mycobacteria was speculated, but never unequivocally proven. Results Here we show by targeted deletion experiments that def can only be deleted from M. smegmatis when an additional copy is present; that prior deletion of tRNAfMet-Formyl Transferase (FMT, encoded by fmt) renders def completely dispensable; and that re-introduction of fmt into a Δdef mutant is not possible – constituting a definitive proof for the essentiality of def in mycobacteria. Conclusions Peptide deformylase is essential in M. smegmatis, but the fact that inactivation of fmt renders the gene completely dispensable, and thus any inhibitor of def useless, casts doubt on the usefulness of PDF as a drug-target in mycobacteria.
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Affiliation(s)
| | | | - Michal Meir
- The Ruth Rappaport Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Daniel Barkan
- Koret School of Veterinary Medicine, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem Rehovot Campus, Rehovot, Israel.
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