Study on the Interaction Between Lignite Fulvic Acid and Cellulase by Multispectral Method and Molecular Docking Simulation
WANG Xiao-xia1, 2*, NIU Hao-ran1, SUN Ji-sheng1, WANG Ya-xiong1, 2, WANG Meng-han1, FU Rui1, 2, MAO Qing1, 2, ZHANG Jian-ling3, WANG Wei4
1. School of Chemistry and Chemical Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China
2. Key Laboratory of Coal Chemical Industry and Comprehensive Utilization of Coal, Inner Mongolia Autonomous Region, Baotou 014010, China
3. Baotou Institute of Agriculture and Animal Husbandry Science and Technology, Inner Mongolia Autonomous Region, Baotou 014010, China
4. Inner Monglia Shennong Sanggu Technology Co., Ltd., Baotou 014060, China
Abstract：In this study, the interaction between fulvic acid (FA) and cellulase (CEL) and its impact on CEL conformation were systematically investigated using fluorescence spectroscopy, synchronous fluorescence spectroscopy, three-dimensional fluorescence spectroscopy, UV-VIS absorption spectroscopy, circular dichroism, infrared spectroscopy, and molecular docking simulations. Fluorescence quenching analysis revealed that the fluorescence intensity of FA decreased in a concentration-dependent manner with increasing CEL concentration. Moreover, the quenching constant decreased with rising temperature, indicating FA's significant static quenching effect on CEL fluorescence. Thermodynamic analysis demonstrated that the interaction between FA and CEL is primarily driven by van der Waals forces and hydrogen bonding, rendering the reaction thermodynamically spontaneous. Förster resonance energy transfer theory suggests potential non-radiative energy transfer between FA and CEL. Ultraviolet-visible absorption and synchronous fluorescence spectra further confirmed the static quenching mechanism and indicated changes in FA's structural density and amino acid residues' microenvironment. Circular dichroism analysis revealed that the binding site of FA and CEL is located in the hydrophobic cavity near the tryptophan residue, leading to reduced hydrophobicity in CEL's secondary structure and an extended peptide chain. This finding corroborates the interaction between FA and CEL and the influence of FA on CEL's secondary structure. Molecular docking studies also showed that the interaction between FA and CEL is predominantly governed by van der Waals forces and hydrogen bonds, achieving stable binding through these interactions, which aligns with the thermodynamic results. Infrared spectroscopy results further support this conclusion.
王晓霞，牛浩然，孙吉盛，王亚雄，王梦涵，付 蕊，马 庆，张建玲，王 炜. 多光谱法和分子对接模拟法研究褐煤黄腐植酸和纤维素酶的相互作用[J]. 光谱学与光谱分析, 2025, 45(08): 2190-2199.
WANG Xiao-xia, NIU Hao-ran, SUN Ji-sheng, WANG Ya-xiong, WANG Meng-han, FU Rui, MAO Qing, ZHANG Jian-ling, WANG Wei. Study on the Interaction Between Lignite Fulvic Acid and Cellulase by Multispectral Method and Molecular Docking Simulation. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2025, 45(08): 2190-2199.
