Intermediate-aided allostery mechanism for α-glucosidase by Xanthene-11v as an inhibitor using residue interaction network analysis

Deciphering Internal Regulatory Patterns within the p53 Core Tetramer: Insights from Community Network Analysis

Gene therapy is one of the most effective strategies for cancer treatment. The p53 protein, commonly known as the "guardian of the genome", plays a critical role in gene activation and tumor suppression. Tetramerization of the p53 core domain is an essential allosteric process that supports its suppression functions. This letter presents a framework to analyze the structure, function, and dynamic connectivity of the p53 tetramer, using community network analysis based on all-atom molecular dynamics simulations. The communities within the p53 monomer exhibit distinct functional roles, while interactions between molecules establish a symmetrical network structure. We identified direct evidence of single, double, and multiple pathway regulations within the p53 tetramer and crucial residue pairs involved in these connections. Our study provides a comprehensive framework to understand the community network of the p53 tetramer, offering new insights into the stable formation of the p53 core tetramer.

Polyphasic approaches to identify and understand α-glucosidase inhibitory potential of secondary metabolites of Withania coagulans fruit

Withania coagulans (WC) is used in traditional and Ayurveda medicine to treat various ailments, including diabetes. Our investigation found that WC fruit hexane extract effectively suppresses α-glucosidase activity (IC50 = 0.013 mg/ml, Ki = 0.012 mg/ml). The purified molecule has an IC50 of 0.004 mg/ml and Ki of 0.0037 mg/ml. FTIR examination indicates distinctive peaks at 3500, 2900, 1770, and 1500 cm-1 corresponding to functional groups OH bending, CH stretching, CO stretching, and CO stretching. GCMS analysis reveals plant secondary metabolites (PSM) such as n-hexadecenoic acid and methyl 9,10-octadecadienoate. NMR confirms the existence of olefinic fatty acids. The bioactive fraction recorded a non-competitive mode of inhibition of α-glucosidase activity. The cytotoxicity exhibited against HELA cell was IC50 0.4 mg/ml and found positive in inhibiting the growth of Bacillus cereus, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Pseudomonas aeruginosa. Additionally, ensemble docking and molecular dynamic simulation showed that, out of the four PSMs examined, methyl 12,13-tetradecadienoate interacted with the α-glucosidase enzyme's allosteric site (BE -128.78 kJ/mol) and changed the configurations of the catalytic sites, as demonstrated by the enzyme's decreased affinity for isomaltose. The study found that PSMs from WC fruit may inhibit α-glucosidase, making them viable candidates for antidiabetic medication development.

Deciphering the binding behavior and interaction mechanism of apigenin and α-glucosidase based on multi-spectroscopic and molecular simulation studies

This study investigated the molecular mechanism underlying the binding interaction between apigenin (API) and α-glucosidase (α-glu) by a combination of experimental techniques and computational simulation strategies. The spontaneously formation of stable API-α-glu complex was mainly driven by hydrogen bonds and hydrophobic forces, leading to a static fluorescence quenching of α-glu. The binding of API induced secondary structure and conformation changes of α-glu, decreasing the surface hydrophobicity of protein. Computational simulation results demonstrated that API could bind into the active cavity of α-glu via its interaction with active residues at the binding site. The important roles of key residues responsible for the binding stability and affinity between API and α-glu were further revealed by MM/PBSA results. In addition, it can be found that the entrance of active site tended to close after API binding as a result of its interaction with gate keeping residues. Furthermore, the structural basis for the binding interaction behavior of API was revealed and visualized by weak interaction analysis. The findings of our study revealed atomic-level mechanism of the interaction between API, which might shed light on the development of better inhibitors.