[Molecular docking of anthocyanins constituents and HER-2 kinase domain]

Anthocyanins are a ubiquitous group of water-soluble plant pigments of the flavonoid family, with anticancer property through HER-2 signaling pathway. Nowadays, molecular docking plays an important role in exposing the active sites and obtaining the bioactive conformation involving protein-ligand interactions. According to the crystal structure of HER-2 kinase domain and 12 main antitumor compounds of anthocyanins as well as ATP, a molecular docking study was performed by MVD program. All 12 compounds could bind to the same cavity of HER-2 kinase domain by high affinity (MolDock Score < -105 kJ/mol for anthocyanidins, < -130 kJ/mol for anthocyanidins-glc), where hydrophobic force and hydrogen bond played key roles. Additionally, this cavity overlapped with ATP binding (MolDock Score = -161 kJ/mol) domain; the binding of anthocyanins presumably interfered the H bond formation between ATP and HER-2. These results indicate that anthocyanins may competitively bind to ATP binding site in HER-2 kinase domain by suppressing HER-2 activation and downstream signaling cascade. This may provide useful theoretical instruction for the molecular mechanism of HER-2 kinase activity inhibition by anthocyanins in cancer prevention and treatment.