Conformational binding mechanism of lysozyme induced by interactions with penicillin antibiotic drugs

In this study we present an in-depth and detailed analysis of the binding process between two antibiotics (cloxacillin and dicloxacillin) and a blood serum protein (lysozyme). Our objectives have been several: to determine, at the atomic level, the structural and conformational changes that take place in both molecular structures once the complex is formed; to investigate the effect that the substitution of a hydrogen atom for a chlorine atom has on the bonding process; and to relate these local modifications with macro molecular parameters. Achieving these goals requires a multi-pronged approach and effective resource management. In our case, we have combined different experimental (isothermal titration calorimetry, UV-vis and fluorescence spectroscopy) and computational techniques (molecular docking and network models), in order to obtain comprehensive and contrasted information of the interaction process. Both approaches have showed an excellent correlation, confirming that there is a single binding site, that both penicillins are moderate binders and hydrogen bond and van der Waals forces are predominant. On the other hand, the small discrepancies between the two techniques highlighted the pressing need to approach the study of these systems from both atomic and macromolecular perspectives. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study provides an in-depth analysis of the binding process between two antibiotics and a blood serum protein, revealing that both penicillins are moderate binders with hydrogen bond and van der Waals forces being predominant. The study emphasizes the importance of approaching these systems from both atomic and macromolecular perspectives.