Effect of Chloramphenicol as Antibiotic on the Structure and Function of Pepsin and Its Mechanism of Action.

Xiaoxia Wang, Jisheng Sun, Zhihua Nie, Litong Ma, Huazheng Sai, Jianguo Cheng, Yunying Liu, Jianguo Duan

Chemistry & biodiversity 2024 Feb

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The interaction between chloramphenicol (CHL) and pepsin (PEP), as well as the impact of CHL on PEP conformation, were investigated using spectroscopic techniques and molecular docking simulations in this study. The experimental results demonstrate that CHL exhibits a static quenching effect on PEP. The thermodynamic parameters indicate that the reaction between CHL and PEP is spontaneous, primarily driven by hydrogen bonding and van der Waals forces. Moreover, the binding distance of r<7 nm suggests the occurrence of Förster's non-radiative energy transfer between these two molecules. In the synchronous fluorescence spectrum, the maximum fluorescence intensity of PEP produced a redshift phenomenon, indicating that CHL was bound to tryptophan residues of PEP. The addition of CHL induces changes in the secondary structure of PEP, as confirmed by the observed alterations in peak values in three-dimensional fluorescence spectra. The UV spectra reveal a redshift of 3 nm in the maximum absorption peak, indicating a conformational change in the secondary structure of PEP upon addition of CHL. Circular dichroism analysis demonstrates significant alterations in the α-helix, β-sheet, β-turn, and random coil contents of PEP before and after CHL incorporation, further confirming its ability to modulate the secondary structure of PEP. © 2023 Wiley-VHCA AG, Zurich, Switzerland.

Citation

Xiaoxia Wang, Jisheng Sun, Zhihua Nie, Litong Ma, Huazheng Sai, Jianguo Cheng, Yunying Liu, Jianguo Duan. Effect of Chloramphenicol as Antibiotic on the Structure and Function of Pepsin and Its Mechanism of Action. Chemistry & biodiversity. 2024 Feb;21(2):e202301554