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Khan, R. M.

Publications and source records attributed to Khan, R. M..

3 recordsLinked to original sources

Molecular Dynamic Investigation of H5N1 Influenza Virus Dual H274Y-I222K Mutation Resistance to Peramivir

In light of the rapid rise of an influenza pandemic, the constant genetic mutations of H5N1 influenza viruses pose a threat. Mutations at the sialic site are often responsible for multiple drug resistance. To design effective new inhibitors, it is necessary to undertake research into the mechanism of resistance of influenza viruses and their rapid mutations. The molecular dynamic simulation technique has been an instrumental tool in understanding how proteins function from an atomic perspective. A thorough investigation has not been conducted using molecular dynamics to examine the impact of these mutations (I222K, H274Y, and H274Y-I222K) on Peramivir. This study investigates the effects of I222K, H274Y, H274Y-I222K substitution on the neuraminidase-Peramivir complex and identifies responsible residues for complex conformations. The mutations caused distorted Peramivir orientation in the enzyme active site, which affected the inhibitors binding. In the presence of various mutations, interaction between protein and ligand became less thermodynamically favorable. We observed the following trend in binding free energy difference: WT<I222<H274Y<H274Y-I222K. As a result of the thermodynamic instability of the mutant complexes, Peramivirs potency is reduced due to impaired binding interactions. Wild type complex displays thermodynamic stability and strong protein-ligand interactions due to their high total energy contributions and low residue flexibility. Based on the energy decomposition analysis, Arg117, Arg224, and Arg292 contributed the largest residual energy for the binding of Peramivir to wild type and mutants. These residues are thought to play a key role in the formation of the binding pocket between Peramivir and neuraminidase. This study provides a basis for investigating the effects of other mutations on Peramivirs efficacy against the H5N1 virus.

bioinformatics↗

A molecular dynamic investigation of Human Rhinovirus 3C Protease Drug Target: Insights towards the design of potential Inhibitors

The 3C protease is distinguished from most proteases due to the presence of cysteine nucleophile that plays an essential role in viral replication. This peculiar structure encompassed with its role in viral replication has promoted 3C protease as an interesting target for therapeutic agents in the treatment of diseases caused by human rhinovirus (HRV). Herein we present a comprehensive molecular dynamics study of the comparison of two potent inhibitors, sg85 and rupintrivir complexed with HRV-3C protease. The binding free energy studies revealed a higher binding affinity for sg85 -58.853 kcal/mol than for rupintrivir -54.0873 kcal/mol and this was found to be in correlation with the experimental data. The energy decomposition analysis showed that, residues Leu 127, Thr 142, Ser 144, Gly 145, Tyr 146, Cys 147, His 161, Val 162, Gly 163, Gly 164, Asn 165, Phe 170 largely contributed to the binding of sg85, whereas His 40, Leu 127 and Gly 163 impacted the binding of rupintrivir. It further showed that His 40, Glu 71, Leu 127, Cys 147 Gly 163 and Gyl 164 are crucial residues that play a key role in ligand-enzyme binding; amongst these residues are residues of the conserved active site (His 40, Glu 71 and Cys 147). These findings provide a comprehensive understanding of the dynamics and structural features and will serve as guidance in the design and development of potent novel inhibitors of HRV. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

bioinformatics↗

Molecular mechanisms underlying Warburgia salutaris effects on oxidative stress and apoptotic parameters in Human Hepatoma Cells

This study aims to determine the molecular effects of Warburgia salutaris extract in HepG2 cells and elucidate the possible mechanisms. The MTT assay was employed to determine cell viability and the half maximal inhibitory concentration (IC50) of Warburgia salutaris-treated in HepG2 cells (0-5mg/ml). Extracellular lactate dehydrogenase and ATP were also quantified as a measure of cell viability. The production of reactive oxygen species (ROS) was assessed by quantifying lipid peroxidation and oxidative DNA damage, and reactive nitrogen species (RNS) in treated HepG2 cells. The cells response to free radicals was assessed by measuring GSH. Stress response antioxidant and apoptotic markers were detected using western blotting and /or qPCR. Cell death parameters assayed included annexin V, caspase activity and necrosis. Single-cell gel electrophoresis (SCGE) was used to visualise DNA damage in the HepG2 cells and confirmed with DNA fragmentation assay. The Hoechst assay allowed the visualisation of the nucleus to assess cell growth and apoptosis. Decreased cell viability was associated with a decreased level of ATP. The presence of oxidative stress was suggested by increased HSP70 and Nrf2 protein expression and confirmed by increase ROS, RNS, GPx and catalase; and a corresponding decrease of SOD2 and glutathione. Caspase 8 showed no significant difference between treatment concentrations, caspase 9 was decreased and caspase 3/7 increased. A reduction in p53 correlated with chromatin changes, increase in comet lengths and DNA fragmentation. NF{kappa}B protein was significantly decreased at the IC50, along with decreased cMyc protein expression. Our findings shows that Warburgia salutaris promotes apoptosis by inducing oxidative stress in HepG2 cells and may be a potential anti-cancer agent that would serve as an alternative to conventional therapeutic agents.

biochemistry↗