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Choi S.B.,Malaysian Institutes of Pharmaceuticals and Nutraceuticals | Choi S.B.,Universiti Sains Malaysia | Choong Y.S.,Universiti Sains Malaysia | Saito A.,Osaka Electro-Communication University | And 8 more authors.
Molecular Informatics | Year: 2014

Present HIV antiviral therapy only targets structural proteins of HIV, but evidence shows that the targeting of accessory proteins will expand our options in combating HIV. HIV-1 Vpr, a multifunctional accessory protein involved in viral infection, replication and pathogenesis, is a potential target. Previously, we have shown that phenyl coumarin compounds can inhibit the growth arrest activity of Vpr in host cells and predicted that the inhibitors' binding site is a hydrophobic pocket on Vpr. To investigate our prediction of the inhibitors' binding site, we docked the coumarin inhibitors into the predicted hydrophobic binding pocket on a built model of Vpr and observed a linear trend between their calculated binding energies and prior experimentally determined potencies. Subsequently, to analyze the inhibitor-protein binding interactions in detail, we built homology models of Vpr mutants and performed docking studies on these models too. The results revealed that structural changes on the binding pocket that were caused by the mutations affected inhibitor binding. Overall, this study showed that the binding energies of the docked molecules are good indicators of the activity of the inhibitors. Thus, the model can be used in virtual screening to identify other Vpr inhibitors and for designing more potent inhibitors. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lee Y.-V.,Universiti Sains Malaysia | Wahab H.A.,Universiti Sains Malaysia | Wahab H.A.,Malaysian Institutes of Pharmaceuticals and Nutraceuticals | Choong Y.S.,Universiti Sains Malaysia
BioMed Research International | Year: 2015

Isocitrate lyase (ICL) is the first enzyme involved in glyoxylate cycle. Many plants and microorganisms are relying on glyoxylate cycle enzymes to survive upon downregulation of tricarboxylic acid cycle (TCA cycle), especially Mycobacterium tuberculosis (MTB). In fact, ICL is a potential drug target for MTB in dormancy. With the urge for new antitubercular drug to overcome tuberculosis treat such as multidrug resistant strain and HIV-coinfection, the pace of drug discovery has to be increased. There are many approaches to discovering potential inhibitor for MTB ICL and we hereby review the updated list of them. The potential inhibitors can be either a natural compound or synthetic compound. Moreover, these compounds are not necessary to be discovered only from MTB ICL, as it can also be discovered by a non-MTB ICL. Our review is categorized into four sections, namely, (a) MTB ICL with natural compounds; (b) MTB ICL with synthetic compounds; (c) non-MTB ICL with natural compounds; and (d) non-MTB ICL with synthetic compounds. Each of the approaches is capable of overcoming different challenges of inhibitor discovery. We hope that this paper will benefit the discovery of better inhibitor for ICL. © 2015 Yie-Vern Lee et al.

Yotmanee P.,Ramkhamhaeng University | Yotmanee P.,Chulalongkorn University | Rungrotmongkol T.,Chulalongkorn University | Wichapong K.,Chulalongkorn University | And 6 more authors.
Journal of Molecular Graphics and Modelling | Year: 2015

The pathogenic dengue virus (DV) is a growing global threat, particularly in South East Asia, for which there is no specific treatment available. The virus possesses a two-component (NS2B/NS3) serine protease that cleaves the viral precursor proteins. Here, we performed molecular dynamics simulations of the NS2B/NS3 protease complexes with six peptide substrates (capsid, intNS3, 2A/2B, 4B/5, 3/4A and 2B/3 containing the proteolytic site between P1 and P1′ subsites) of DV type 2 to compare the specificity of the protein-substrate binding recognition. Although all substrates were in the active conformation for cleavage reaction by NS2B/NS3 protease, their binding strength was somewhat different. The simulated results of intermolecular hydrogen bonds and decomposition energies suggested that among the ten substrate residues (P5-P5′) the P1 and P2 subsites play a major role in the binding with the focused protease. The arginine residue at these two subsites was found to be specific preferential binding at the active site with a stabilization energy of <-10 kcal mol-1. Besides, the P3, P1′, P2′ and P4′ subsites showed a less contribution in binding interaction (<-2 kcal mol-1). The catalytic water was detected nearby the carbonyl oxygen of the P1 reacting center of the capsid, intNS3, 2A/2B and 4B/5 peptides. These results led to the order of absolute binding free energy (ΔGbind) between these substrates and the NS2B/NS3 protease ranked as capsid > intNS3 > 2A/2B > 4B/5 > 3/4A > 2B/3 in a relative correspondence with previous experimentally derived values. © 2015 Elsevier Inc. All rights reserved.

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