Decoding the binding interaction of steroidal pyridines with bovine serum albumin using spectroscopic and molecular docking techniques

Abstract

The present study reports a comprehensive and conformational aspect of binding of steroidal pyridines (1–6) with a model transport protein, bovine serum albumin (BSA) by fluorescence, UV–visible, circular dichroism, and molecular docking techniques. Quenching of BSA emission was attributed to the formation of the ground state complex after the compound (1–6) binds to the backbone of the protein. Synchronous fluorescence spectra reveals changes in the microenvironment of the aromatic residues. UV–visible absorption spectra further reiterate the quenching mechanism to be static and binding of compound (1–6) results in the formation of a ground-state complex. Circular dichroism spectra indicated that compound 1–3 causes unfolding and compound 4–6 leads to the stabilization of the protein structure. In addition, a molecular docking study revealed the binding pocket for the formation of the ligand–protein complex through hydrogen bonding and hydrophobic interactions. Furthermore, hemolytic activity suggested that the compounds (1–6) are biocompatible in nature. Evaluation of such steroid-protein interaction helps in better understanding of the biomolecular interaction of steroidal compounds with biomacromolecule and opens up new approaches in steroid based drug-design process.