Understanding the interaction behaviors and conformational changes of tea protein with structurally diverse flavonoids.

This study systematically investigated the interaction behaviors and conformational changes of the tea protein (TP) with three flavonoids (chrysin, apigenin, and luteolin) through various experiments and computational simulations. Notably, TP formed stable and homogeneous complexes with all three flavonoids, with TP-luteolin complex being the most stable. Surface hydrophobicity and multispectral analyses revealed that flavonoid binding significantly changed the TP surface properties and conformational rearrangements. Fluorescence spectroscopy revealed a static quenching mechanism, with quenching abilities in the following order: Luteolin > apigenin > chrysin. Thermodynamic analysis confirmed the spontaneous nature of the interactions, which were primarily driven by hydrogen bonding and van der Waals forces. Infrared spectroscopy further confirmed the protein conformation changes. Molecular docking and simulations provided complementary insights into the binding mechanisms at the atomic level. Overall, our findings provide structural insights into TP-flavonoid interactions.