Probing the interaction of Rivastigmine Tartrate, an important Alzheimer's drug, with serum albumin: Attempting treatment of Alzheimer's disease

Abstract

The present study was aimed at investigating the binding between an important drug of Alzheimer's therapy, Rivastigmine tartrate (RT), with Bovine serum albumin (BSA). BSA is a model protein that is increasingly being used for studies related to drug-protein interaction owing to its structural similarity with human serum albumin (HSA) which is extremely abundant in the circulatory system comprising around 60% of the total plasma protein. Fluorescence spectroscopy implied that complex formation is taking place between BSA and RT; binding constant calculated was of the order of 104 M−1 implicative of the strength of this interaction. Fluorescence spectroscopy was carried out at three different temperatures in a bid to find out the operative mode of quenching; static quenching was taking place for RT-BSA interaction with a binding constant of 2.5 × 104 M−1 at 298 K. Further, changes in Far UV CD spectra clearly implied that RT induces structural transition in BSA suggestive of RT-BSA complex formation. The negative value of ∆G0 as obtained from fluorescence spectroscopy and isothermal titration calorimetry (ITC) suggests the reaction to be spontaneous and thermodynamically favorable. Additionally, molecular docking was employed to investigate different forces and critical residues involved in RT-BSA interaction. Furthermore, all-atom molecular dynamics simulation for 50 ns was performed on the BSA-RT complex to investigate its conformational behavior, stability and dynamics.