Characterizing the binding interactions of sodiumbenzoatewithlysozymeat the molecular level using multi-spectroscopy, ITC and modeling methods

Chengqian Huo; Guiliang Liu; Mengchen Xu; Xiangxiang Li; Wansong Zong; Rutao Liu

doi:10.1016/j.saa.2021.120213

Characterizing the binding interactions of sodiumbenzoatewithlysozymeat the molecular level using multi-spectroscopy, ITC and modeling methods

Spectrochim Acta A Mol Biomol Spectrosc. 2021 Dec 15:263:120213. doi: 10.1016/j.saa.2021.120213. Epub 2021 Jul 22.

Authors

Chengqian Huo¹, Guiliang Liu², Mengchen Xu³, Xiangxiang Li¹, Wansong Zong⁴, Rutao Liu⁵

Affiliations

¹ School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong, 266237, PR China.
² Shandong Institute for Food and Drug Control, 2749# Xinluo street, high tech Zone, Jinan City, Shandong Province 250100, PR China.
³ School of Environmental and Municipal Engineering, Qingdao University of Technology, Shandong Province, No. 11 Fushun Road, Qingdao 266033, PR China.
⁴ College of Population, Resources and Environment, Shandong Normal University, 88# East Wenhua Road, Jinan 250014, PR China.
⁵ School of Environmental Science and Engineering, Shandong University, China-America CRC for Environment & Health, Shandong Province, 72# Jimo Binhai Road, Qingdao, Shandong, 266237, PR China. Electronic address: rutaoliu@sdu.edu.cn.

PMID: 34325175
DOI: 10.1016/j.saa.2021.120213

Abstract

In this paper, we mainly study the interaction mechanism between food additives and antioxidant enzymes. Spectral methods were used to study the effect of sodium benzoate on the structure and function of lysozyme at the molecular level. Multi-spectroscopic results showed that sodium benzoate statically quenched the intrinsic fluorescence of lysozyme, formed complexes with lysozyme, increased the polarity of the aromatic amino acid, effected the molecular skeleton of lysozyme and stretched the secondary structure. The molecular docking and isothermal titration calorimetry (ITC) results showed that sodium benzoate entered the depression of the surface of lysozyme molecule both through hydrophobic interaction and hydrogen bond. Sodium benzoate was linked to tryptophan (Trp-63) by a hydrogen bond with a bond length of 2.48 Å. Thermodynamic studies showed that the combination was spontaneous, as the values of the enthalpy change (ΔH) and the entropy change (ΔS) were calculated to be 12.558 kJmol^-1 and 25 kJmol^-1k^-1, respectively. Enzyme activity determination showed that Sodium benzoate increased lysozyme activity by 22.31%. This study can provide experimental support for evaluating the edible safety of sodium benzoate.

Keywords: Interaction mechanism; Lysozyme; Sodium benzoate; Spectroscopy.

MeSH terms

Binding Sites
Calorimetry
Molecular Docking Simulation*
Protein Binding
Spectrometry, Fluorescence
Spectrum Analysis
Thermodynamics