Preliminary Study of the Interaction between Chlorogenic Acid and Myofibrillar Protein Based on Multispectral Techniques

In this study, the binding properties and structural changes associated with the interaction of Coregonus peled myofibrillar protein (MP) and different concentrations (6, 30, 150, and 300 µmol/g) of chlorogenic acid (CA) were investigated. The CA-MP complexes were formed at 25 °C, and the physical and chemical properties (total sulfhydryl groups, surface hydrophobicity), changes in secondary and tertiary structure (measured by Fourier-infrared spectroscopy, synchrotron fluorescence, and 3D fluorescence), and binding properties (measured by UV spectra, fluorescence quenching, and thermodynamic parameters) of the CA-MP complexes were measured. The results showed that at concentrations of 300 µmol/g CA, the total sulfhydryl content and surface hydrophobicity of MP decreased abruptly by 25.65% and 40.26%, respectively (P<0.05). Unfolding of the MP secondary structure and reductions in the α-helix content to 11.73% were observed, adversely affecting the structural stability of the protein. The synchronous and three-dimensional fluorescence spectra of MP showed that CA led to quenching of the protein fluorescence, with tryptophan showing 7.90% higher quenching compared with tyrosine. The UV spectra and fluorescence quenching data confirmed the formation of the CA-MP complexes, with complexes formation inducing static quenching, while the thermodynamic parameters further confirmed that hydrophobic forces dominated the interaction. The findings of the study provide valuable information on the interaction between polyphenols and Coregonus peled MP, as well as a reference for further investigations into the mechanisms underlying interactions between Coregonus peled myosin and polyphenols of different structures.