New insights into the interactions between the antibiotic enrofloxacin and fish protein by spectroscopic, thermodynamic, and theoretical simulation approaches

Xinyuan Hu; Shaofeng Yuan; Aying Wen; Qingmin Chen; Hang Yu; Yahui Guo; Yuliang Cheng; Weirong Yao

doi:10.1016/j.saa.2024.125658

New insights into the interactions between the antibiotic enrofloxacin and fish protein by spectroscopic, thermodynamic, and theoretical simulation approaches

Spectrochim Acta A Mol Biomol Spectrosc. 2024 Dec 24:330:125658. doi: 10.1016/j.saa.2024.125658. Online ahead of print.

Authors

Xinyuan Hu¹, Shaofeng Yuan², Aying Wen¹, Qingmin Chen³, Hang Yu¹, Yahui Guo¹, Yuliang Cheng¹, Weirong Yao¹

Affiliations

¹ State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu Province, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, China.
² State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi, Jiangsu Province, China; School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu Province, China. Electronic address: yuanshaofeng@jiangnan.edu.cn.
³ College of Ocean Food and Biological Engineering, Jimei University, Xiamen 361021, China.

PMID: 39733711
DOI: 10.1016/j.saa.2024.125658

Abstract

In this study, myofibrillar proteins (MPs) from crucian carp were utilized as a model to investigate the binding mechanism between fish proteins and antibiotic residues. Fluorescence quenching confirmed the static quenching (K_sv = 1.89 × 10⁴ M^-1 s^-1, K_q = 1.89 × 10¹² M^-1 s^-1) and effective binding (K_b = 5.66 × 10⁶ M^-1) of Enrofloxacin (ENRO) to MPs. Fourier-transform infrared spectroscopy and circular dichroism spectroscopy revealed that ENRO binding altered the secondary structure of MPs. The interaction mechanism, primarily driven by hydrogen bonding, electrostatic, and hydrophobic interactions (ΔH⁰ < 0, ΔS⁰ > 0), was elucidated using isothermal titration calorimetry. The ΔH⁰, -TΔS⁰ and ΔG⁰ values of the binding reaction between MPs and ENRO were -5.98 kJ/mol, -32.57 kJ/mol and -38.55kJ/mol. Molecular docking further verified the interaction forces, identifying key amino acid residues (Phe-40, His-93, and Lys-42) involved in ENRO binding. Additionally, protein carbonylation results demonstrated that even at maximum residue limits, ENRO accelerated MPs oxidation, further confirming the binding of the two. This study can provide theoretical support for the research of the dissipation fate of bound state residues in aquatic products.

Keywords: Binding interaction; Bound antibiotics; Enrofloxacin; Myofibrillar proteins; Protein carbonylation.