muramidase and myricetin

The interaction between myricetin and dihydromyricetin with trypsin, α-chymotrypsin and lysozyme was investigated using multispectral and molecular docking methods. The results of fluorescence quenching revealed that myricetin and dihydromyricetin could quench the intrinsic fluorescence of three different proteinases through a static quenching procedure. The binding constant and number of binding sites at different temperatures were measured. The thermodynamic parameters obtained at different temperatures showed van der Waals interactions and hydrogen bonds played the main roles in the interaction of myricetin with trypsin and lysozyme, hydrophobic force was dominant both in myricetin with α-chymotrypsin interaction and dihydromyricetin with trypsin and lysozyme interaction, as for the electrostatic forces, it was mainly the driving force in dihydromyricetin binding to α-chymotrypsin. There was non-radiative energy transfer between three proteinases and myricetin or dihydromyricetin with high probability. The microenvironment of trypsin, α-chymotrypsin and lysozyme is changed. The docking studies revealed that myricetin and dihydromyricetin entered the hydrophobic cavity of three proteinases and formed hydrogen bonds. The binding affinity of myricetin or dihydromyricetin is different with the trypsin, α-chymotrypsin and lysozyme due to the different molecular structure.

Topics: Binding Sites; Chymotrypsin; Flavonoids; Flavonols; Molecular Docking Simulation; Muramidase; Protein Binding; Spectrometry, Fluorescence; Thermodynamics; Trypsin

Myricetin is a natural flavonol found in many grapes, berries, fruits, vegetables, and herbs as well as other plants. Recent studies have identified potential antiamyloidogenic activity for this compound. In this study, the kinetics of amyloid fibril formation by hen egg white lysozyme (HEWL) and the antifibril-forming activity of myricetin were investigated. We demonstrate that myricetin significantly inhibits the fibrillation of HEWL and the inhibitory effect is dose-dependent. Interestingly, the inhibitory effect toward HEWL fibrillation was stronger than that exerted by the previously characterized fibril-forming inhibitor quercetin, which has high structural similarity with myricetin. Spectrofluorometric and computational studies suggest that the mechanism underlying the inhibitory action of myricetin at a molecular level is to reduce the population of partially unfolded HEWL intermediates. This action is achieved by the tight binding of myricetin to the aggregation-prone region of the β-domain of HEWL and linking to the relatively stable α-domain, thus resulting in the inhibition of amyloid fibril formation.

Topics: Amyloid; Animals; Chickens; Flavonoids; Kinetics; Models, Molecular; Muramidase; Protein Aggregates; Protein Structure, Secondary