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Rethinking the MtInhA tertiary and quaternary structure flexibility: a molecular dynamics view. J Mol Model 2022; 28:140. [PMID: 35534695 DOI: 10.1007/s00894-022-05135-6] [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: 07/22/2021] [Accepted: 04/30/2022] [Indexed: 10/18/2022]
Abstract
Flexibility and function are related properties in the study of protein dynamics. Flexibility reflects in the conformational potential of proteins and thus in their functionalities. The presence of interactions between protein-ligands and protein-protein complexes, substrates, and environmental changes can alter protein plasticity, acting from the rearrangement of the side chains of amino acids to the folding/unfolding of large structural motifs. To evaluate the effects of the flexibility in protein systems, we defined the enzyme 2-trans-enoyl-ACP (CoA) reductase from Mycobacterium tuberculosis, or MtInhA, as our target system. MtInhA is biologically active as a tetramer in solution; however, computational studies commonly use the monomer justifying the independence of its active sites due to their distances. However, differences in flexibility between tertiary and quaternary structures could present impact on the size of the active site, influencing the drug discovery process. In this study, we investigated the influence of flexibility restrictions in A- and B-loops of the MtInhA in order to suggest a monomeric structure that describes the conformational behavior of the tetrameric system. Overall, we observed that simulations where restrictions were applied to the A- and B-loops present a more similar behavior to the native structure when compared to unrestricted simulations. Therefore, our work presents a monomeric model of MtInhA, which has conformational characteristics of the biologically active structure. Thus, the data obtained in this work can be applied to the MtInhA system for the generation of more reliable flexible models for molecular docking experiments, and also for the performance of longer simulations by molecular dynamics and with a lower computational cost.
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Prasad MS, Bhole RP, Khedekar PB, Chikhale RV. Mycobacterium enoyl acyl carrier protein reductase (InhA): A key target for antitubercular drug discovery. Bioorg Chem 2021; 115:105242. [PMID: 34392175 DOI: 10.1016/j.bioorg.2021.105242] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 07/16/2021] [Accepted: 08/02/2021] [Indexed: 10/20/2022]
Abstract
Enoyl acyl carrier protein reductase (InhA) is a key enzyme involved in fatty acid synthesis mainly mycolic acid biosynthesis that is a part of NADH dependent acyl carrier protein reductase family. The aim of the present literature is to underline the different scaffolds or enzyme inhibitors that inhibit mycolic acid biosynthesis mainly cell wall synthesis by inhibiting enzyme InhA. Various scaffolds were identified based on the screening technologies like high throughput screening, encoded library technology, fragment-based screening. The compounds studied include indirect inhibitors (Isoniazid, Ethionamide, Prothionamide) and direct inhibitors (Triclosan/Diphenyl ethers, Pyrrolidine Carboxamides, Pyrroles, Acetamides, Thiadiazoles, Triazoles) with better efficacy against drug resistance. Out of the several scaffolds studied, pyrrolidine carboxamides were found to be the best molecules targeting InhA having good bioavailability properties and better MIC. This review provides with a detailed information, analysis, structure activity relationship and useful insight on various scaffolds as InhA inhibitors.
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Affiliation(s)
- Mayuri S Prasad
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MS, India
| | - Ritesh P Bhole
- Dr. D. Y. Patil Institute of Pharmaceutical Sciences and Research, Pimpri, Pune 411018, Maharashtra, India
| | - Pramod B Khedekar
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur 440033, MS, India.
| | - Rupesh V Chikhale
- UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom.
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Agarwal S, Verma E, Kumar V, Lall N, Sau S, Iyer AK, Kashaw SK. An integrated computational approach of molecular dynamics simulations, receptor binding studies and pharmacophore mapping analysis in search of potent inhibitors against tuberculosis. J Mol Graph Model 2018; 83:17-32. [PMID: 29753941 DOI: 10.1016/j.jmgm.2018.04.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 04/26/2018] [Accepted: 04/27/2018] [Indexed: 12/15/2022]
Abstract
Tuberculosis is an infectious chronic disease caused by obligate pathogen Mycobacterium tuberculosis that affects millions of people worldwide. Although many first and second line drugs are available for its treatment, but their irrational use has adversely lead to the emerging cases of multiple drug resistant and extensively drug-resistant tuberculosis. Therefore, there is an intense need to develop novel potent analogues for its treatment. This has prompted us to develop potent analogues against TB. The Mycobacterium tuberculosis genome provides us with number of validated targets to combat against TB. Study of Mtb genome disclosed six epoxide hydrolases (A to F) which convert harmful epoxide into diols and act as a potential drug target for rational drug design. Our current strategy is to develop such analogues which inhibits epoxide hydrolase enzyme present in Mtb genome. To achieve this, we adopted an integrated computational approach involving QSAR, pharmacophore mapping, molecular docking and molecular dynamics simulation studies. The approach envisaged vital information about the role of molecular descriptors, essential pharmacophoric features and binding energy for compounds to bind into the active site of epoxide hydrolase. Molecular docking analysis revealed that analogues exhibited significant binding to Mtb epoxide hydrolase. Further, three docked complexes 2s, 37s and 15s with high, moderate and low docking scores respectively were selected for molecular dynamics simulation studies. RMSD analysis revealed that all complexes are stable with average RMSD below 2 Å throughout the 10 ns simulations. The B-factor analysis showed that the active site residues of epoxide hydrolase are flexible enough to interact with inhibitor. Moreover, to confirm the binding of these urea derivatives, MM-GBSA binding energy analysis were performed. The calculations showed that 37s has more binding affinity (ΔGtotal = -52.24 kcal/mol) towards epoxide hydrolase compared to 2s (ΔGtotal = -51.70 kcal/mol) and 15s (ΔGtotal = -49.97 kcal/mol). The structural features inferred in our study may provide the future directions to the scientists towards the discovery of new chemical entity exhibiting anti-TB property.
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Affiliation(s)
- Shivangi Agarwal
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India
| | - Ekta Verma
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India
| | - Vivek Kumar
- Department of Plant and Soil Sciences, University of Pretoria, South Africa
| | - Namrita Lall
- Department of Plant and Soil Sciences, University of Pretoria, South Africa
| | - Samaresh Sau
- Use-inspired Biomaterials & integrated Nano Delivery (U-BiND) Systems Laboratory, Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
| | - Arun K Iyer
- Use-inspired Biomaterials & integrated Nano Delivery (U-BiND) Systems Laboratory, Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA; Molecular Imaging Program, Karmanos Cancer Institute, Detroit, MI, USA
| | - Sushil K Kashaw
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India.
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Kumar V, Jhamb SS, Sobhia ME. Cell wall permeability assisted virtual screening to identify potential direct InhA inhibitors of Mycobacterium tuberculosis and their biological evaluation. J Biomol Struct Dyn 2017; 36:3274-3290. [PMID: 28974157 DOI: 10.1080/07391102.2017.1387176] [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: 10/18/2022]
Abstract
The arising cases of isoniazid-resistance have motivated research interests toward new class of molecules known as direct InhA inhibitors. Here, a combine approach of shape-based pharmacophore and descriptor-based 2D QSAR was used to identify the potential direct InhA inhibitors. The approach is duly assisted with in vitro testing and molecular dynamics simulations. A combination of empirical parameters was derived to use as a filter for cell wall permeability while 2D QSAR was used as another filter to predict the biological activity. Both filters were applied to prioritize the molecules for biological evaluation against anti-TB activity. It led to 6 potential molecules which showed > 90% inhibition of H37Rv strain of Mycobacterium tuberculosis in BACTEC assay. Further, MMGBSA binding free energy of identified molecules was compared with available highly potent molecule, 5-hexyl-2-(2-methylphenoxy) phenol (IC50 = 5nM) using molecular dynamics simulations. It showed two molecules with comparatively higher affinity toward InhA as compared to potent molecule. It indicated the candidature of identified molecules to be further considered in anti-TB drug development pipeline.
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Affiliation(s)
- Vivek Kumar
- a Department of Pharmacoinformatics , National Institute of Pharmaceutical Education and Research , Sector-67, S.A.S. Nagar, Punjab 160062 , India
| | - Sarbjit Singh Jhamb
- b Common Biological Testing Lab (CBTL), Department of Pharmaceuticals , National Institute of Pharmaceutical Education and Research (NIPER) , Sector-67, S.A.S. Nagar, Punjab 160062 , India
| | - M Elizabeth Sobhia
- a Department of Pharmacoinformatics , National Institute of Pharmaceutical Education and Research , Sector-67, S.A.S. Nagar, Punjab 160062 , India
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Kumar V, Sobhia ME. Molecular dynamics-based investigation of InhA substrate binding loop for diverse biological activity of direct InhA inhibitors. J Biomol Struct Dyn 2016; 34:2434-52. [DOI: 10.1080/07391102.2015.1118410] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Vivek Kumar
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar 160 062, Punjab, India
| | - M. Elizabeth Sobhia
- Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Sector 67, S.A.S. Nagar 160 062, Punjab, India
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Aqueous Molecular Dynamics Simulations of the M. tuberculosis Enoyl-ACP Reductase-NADH System and Its Complex with a Substrate Mimic or Diphenyl Ethers Inhibitors. Int J Mol Sci 2015; 16:23695-722. [PMID: 26457706 PMCID: PMC4632722 DOI: 10.3390/ijms161023695] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/18/2015] [Accepted: 09/08/2015] [Indexed: 12/22/2022] Open
Abstract
Molecular dynamics (MD) simulations of 12 aqueous systems of the NADH-dependent enoyl-ACP reductase from Mycobacterium tuberculosis (InhA) were carried out for up to 20–40 ns using the GROMACS 4.5 package. Simulations of the holoenzyme, holoenzyme-substrate, and 10 holoenzyme-inhibitor complexes were conducted in order to gain more insight about the secondary structure motifs of the InhA substrate-binding pocket. We monitored the lifetime of the main intermolecular interactions: hydrogen bonds and hydrophobic contacts. Our MD simulations demonstrate the importance of evaluating the conformational changes that occur close to the active site of the enzyme-cofactor complex before and after binding of the ligand and the influence of the water molecules. Moreover, the protein-inhibitor total steric (ELJ) and electrostatic (EC) interaction energies, related to Gly96 and Tyr158, are able to explain 80% of the biological response variance according to the best linear equation, pKi = 7.772 − 0.1885 × Gly96 + 0.0517 × Tyr158 (R2 = 0.80; n = 10), where interactions with Gly96, mainly electrostatic, increase the biological response, while those with Tyr158 decrease. These results will help to understand the structure-activity relationships and to design new and more potent anti-TB drugs.
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Insights into the bonding pattern for characterizing the open and closed state of the substrate-binding loop in Mycobacterium tuberculosis InhA. Future Med Chem 2014; 6:605-16. [DOI: 10.4155/fmc.14.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Direct InhA inhibitors, which interact with the substrate-binding loop (SBL) and order it into a closed state, are thought to be potential anti-multidrug-resistant tuberculosis molecules. Thus, developing parameters to distinguish between the open and closed state of SBL can help in screening the potent inhibitors with loop ordering properties. Results: We report empirical parameters to differentiate the 'open' and 'closed' conformation of SBL by comprehensive analysis of InhA crystal structures. The 'open' state of SBL was observed with intra- and inter-loop H-bonding within the residues pair, G205–G208 and L207–I105, respectively, while the 'closed' conformation is found with H-bonding within the residues pair: L207–E210 and A206–I105. Moreover, potent inhibitors (IC50, 5.3–5160 nM) are observed to make hydrophobic interactions with residues of SBL, particularly with A198 in the structures with closed state of SBL. Conclusion: The observed set of H-bonding pattern and hydrophobic contact with residues of SBL can be utilized as a filter to evaluate novel inhibitors for their SBL ordering properties and potencies using the molecular dynamic simulation in the virtual screening of direct InhA inhibitors.
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