Recognition and binding of β-lactam antibiotics to bovine serum albumin by frontal affinity chromatography in combination with spectroscopy and molecular docking

Serum albumins are the most abundant carrier proteins in blood plasma and participate in the binding and transportation of various exogenous and endogenous compounds in the body. This work was designed to investigate the recognition and binding of three typical beta-lactam antibiotics including penicillin G (Pen G), penicillin V (Pen V) and cefalexin (Cef) with bovine serum albumin (BSA) by frontal affinity chromatography in combination with UV-vis absorption spectra, fluorescence emission spectra, binding site marker competitive experiment and molecular docking under simulated physiological conditions. The results showed that a BSA only bound with one antibiotic molecule in the binding process, and the binding constants for Pen G-BSA, Pen V-BSA and Cef-BSA complexes were 4.22 x 10(1), 4.86 x 10(2) and 3.32 x 10(3) (L/mol), respectively. All the three beta-lactam antibiotics were mainly inserted into the subdomain HA (binding site 1) of BSA by hydrogen bonds and Van der Waals forces. The binding capacity between the antibiotics and BSA was closely related to the functional groups and flexibility of side chains in antibiotics. This study provided an important insight into the molecular recognition and binding interaction of BSA with beta-lactam antibiotics, which may be a useful guideline for the innovative clinical medications and new antibiotic designs with effective pharmacological properties. (C) 2016 Elsevier B.V. All rights reserved.