Binding of TEM-1 beta-lactamase to beta-lactam antibiotics by frontal affinity chromatography

•An equation is developed to describe the protein-ligand interactions in FAC.•We can get the main interaction parameters by the equation.•The equation is tested and validated by experimentation.

TEM-1 beta-lactamases can accurately catalyze the hydrolysis of the beta-lactam rings in beta-lactam antibiotics, which make beta-lactam antibiotics lose its activity, and the prerequisite for the hydrolysis procedure in the binding interaction of TEM-1 beta-lactamases with beta-lactam antibiotics is the beta-lactam rings in beta-lactam antibiotics. Therefore, the binding of TEM-1 beta-lactamase to three beta-lactam antibiotics including penicillin G, cefalexin as well as cefoxitin was explored here by frontal affinity chromatography in combination with fluorescence spectra, adsorption and thermodynamic data in the temperature range of 278-288 K under simulated physiological conditions. The results showed that all the binding of TEM-1 beta-lactamase to the three antibiotics were spontaneously exothermic processes with the binding constants of 8.718 × 103, 6.624 × 103 and 2.244 × 103 (mol/L), respectively at 288 K. All the TEM-1 beta-lactamases were immobilized on the surface of the stationary phase in the mode of monolayer and there existed only one type of binding sites on them. Each TEM-1 beta-lactamase bound with only one beta-lactam antibiotic and hydrogen bond interaction and Van der Waals force were the main forces between them. This work provided an insight into the binding interactions between TEM-1 beta-lactamases and beta-lactam antibiotics, which may be beneficial for the designing and developing of new substrates resistant to TEM-1 beta-lactamases.