Abstract
Flavonoids exhibit a wide variety of biological effects and hold great protein-binding potential. In this study, we take quercetin, an extensively studied flavonoid, as an example to investigate the structural basis underlying their excellent protein-binding ability. Through calculating the pocket similarity of quercetin-binding proteins and comparing the binding modes between quercetins bound with different proteins, it was found that the great protein-binding capacity of quercetin not only arises from the structural conservation of target proteins, but also stems from its unique structure, in which molecular rigidity and flexibility is well-balanced and various chemical interactions could be formed between the small molecule and protein targets.