Investigative on the molecular mechanism of novel antioxidation peptides by 3D-QSAR, in vitro assay and MD simulations

Abstract

Three novel antioxidant peptides MHW, YHW and FHW were designed by the analysis of 3D-QSAR. Two accurate CoMFA (Q2 = 0.886 and R2 = 0.988) and CoMSIA (Q2 = 0.737 and R2 = 0.955) models were established. The FTC assay showed that activities of the new peptides on lipid peroxidation is significantly better than that of the template molecule LHW. The results of erythrocyte hemolysis assay demonstrated that MHW, YHW and FHW significantly inhibited AAPH-induced erythrocyte hemolysis by scavenging free radicals at the cellular level. It caused the restoration of intracellular antioxidant enzyme (GSH, CAT and SOD) activities at an acceptable pace and the silencing of intracellular MDA formation. Furthermore, MTT toxicity assay showed that the novel antioxidant peptides had good biocompatibility and no cytotoxicity. Molecular docking and molecular dynamics simulations were used to investigate the molecular mechanism. The results showed that Ser363, Arg380, Asn414 and Arg415 residues played key roles in the antioxidant activity of MHW, YHW and FHW. And they mainly binded to the important residues of Keap1 protein stably by electrostatic force, van der Waals force, H-bonds and hydrophobic interactions, which can better fit the Kelch pocket structural domain of Keap1. Therefore, MHW, YHW and FHW had strong potential to interfere with Keap1-Nrf2 interaction and promoted the enzymatic expression of Nrf2-ARE downstream target pathway.