A molecular bridge-like binding mode of buspirone to BSA: Multispectroscopic and molecular docking investigation

The anxiolytic psychotropic drug buspirone from the azapirone class of tranquilizer treats seizures, panic disorder, and anxiety disorder. The buspirone's binding interaction to bovine serum albumin (BSA) was investigated using UV -visible, fluorescence spectroscoy with molecular docking methods. Findings are indicative that buspirone is bound simultaneously on two subdomains IIA and IIIA of albumin through conventional hydrogen bond, carbon -hydrogen bonds, van-der-Waals forces and alkyl interactions. The binding sites (n) and binding constant (K-b) of the buspirone-BSA complex were about 2 and 1.64217x10(5) M- (1)at 298 K. The buspirone binding to BSA was spontaneous and enthalpy -driven. The buspirone's binding interaction with BSA brings about a minor conformation change in BSA and apparent conformation change in buspirone, suggesting that the flexibility of buspirone also played a role in the cumulative stability of the buspirone-BSA complex.