基于多光谱法与分子对接探究青蒿乙素与牛血清白蛋白的结合机制OA

OBJECTIVE To investigate the binding mechanism of arteannuin B(ATB)with bovine serum albumin(BSA).METHODS Spectroscopic techniques combined with molecular docking were employed.UV-vis and fluorescence spectroscopy were used to characterize the interactions.The binding constant(Ka)and number of binding sites(n)were calculated using the double-logarithmic modified Stern-Volmer equation while thermodynamic parameters were derived from Van't Hoff analysis.The binding sites were identified by competitive displacement experiments using site-specific probes.Confor-mational changes were monitored by Raman spectroscopy.Molecular docking was performed using Molecular Operating Environment(MOE)software to elucidate the binding mode and interaction forces.RESULTS ATB formed a ground-state complex with BSA with a binding constant of(2.15-6.18)×10-4 L·mol-1(296-310 K)and the number of binding sites was close to 1.The binding was spontane-ous and exothermic,driven primarily by hydrogen bonding and van der Waals forces.Competitive experiments confirmed SiteⅠ(subdomain ⅡA)as the primary binding location.Raman spectroscopy revealed altered microenvironments around tyrosine and tryptophan residues and secondary structural changes in BSA(decreased α-helix,increased β-sheet content).Molecular docking showed ATB inser-tion into the hydrophobic cavity of SiteⅠ,forming two hydrogen bonds with Arg256 and van der Waals interactions with Tyr149,Trp213,His241,Ser286,Ile289,and Phe222(binding energy:-7.9 kcal·mol-1).CONCLUSION ATB forms a 1:1 complex with BSA at SiteⅠ,with hydrogen bonds and van der Waals forces as the dominant interactions.