The Effect of Luteolin and Luteoloside on the Secondary Structure of Lysozyme

Yu Wu,Pin Lv,Yan Zhang,Rong Wang,Lijian Cui,Ning Chen,Ling-Ling Qu ,Yucong Huang

doi:10.1155/2021/5523965

Abstract

The changes of lysozyme conformation in the absence and presence of luteolin and luteoloside were investigated by spectral analysis including fluorescence, UV, CD, Raman, and ATR-FTIR, and the biological activity of lysozyme was investigated by lysozyme assay kit. The results showed that the microenvironment hydrophobicity of lysozyme increased and peptide extension decreased with the addition of luteolin or luteoloside. The α-helix of lysozyme might be influenced by luteolin or luteoloside, and its relative content had a significant difference after adding luteolin or luteoloside by the ATR-FTIR method, which was reconfirmed by CD and Raman spectra. The lysozyme activity changed obviously after adding luteolin or luteoloside. All of the conclusions above indicated the active site of lysozyme in the α-helix might be influenced by luteolin and luteoloside.

Highlights

Lysozyme (LYSO), called muramidase, killing or inhibiting the bacteria with little drug resistance, is an important immune factor widely existing in many tissues of the human body [1, 2]
Lysozyme Secondary Structure Change. e active site of lysozyme is mainly in the helices region, so we further focus on studying the change of lysozyme α-helix. e spectroscopic methods have shown that lysozyme conformation changed with the addition of luteolin or luteoloside. e hydroxyl group on the benzene ring of flavonoid might combine with -NH-CO- in lysozyme to change the stretching vibration of C O, and the hydrogen on the hydroxyl group of benzene ring might form a hydrogen bond with C-N in lysozyme, changing the stretching vibration of C-N, which increased lysozyme microenvironment hydrophobicity and made the peptide chain structure more compact. ose would influence the secondary structure of the enzyme and change the spectra characteristics
Fluorescence and UV spectra analyses proved that luteolin and luteoloside could combine with lysozyme

Summary

Introduction

Lysozyme (LYSO), called muramidase, killing or inhibiting the bacteria with little drug resistance, is an important immune factor widely existing in many tissues of the human body [1, 2]. It can lyse cell walls of bacteria [3], without degradation to the cells in the human body. Lysozyme is clinically available to promote the repair of injured tissues, to correct the degree of immune activation, and to reduce the acute inflammatory reaction, especially in burn wound infection and herpes treatment [4]. Lysozyme has a globular fold divided into two domains, whose native conformation displays four α-helix structures and a three-strand antiparallel β-sheet [5] which consist of 129 amino acid residues, including six Trp residues, three of which (Trp 62, Trp 63, and Trp 108) locate in the active pocket of the helices domain of lysozyme [6]

Methods

Results

Conclusion