β-Amyrin synthase from P ginseng (β-AS) catalyzes the biosynthesis of the cyclization of oxidosqualene into Oleanane-type saponins, thereby reducing the amount of steroid formation. However, the 3D structure of β-AS has not been firmly established. To finding the novel inhibitors, a 3D structure model of β-AS protein was constructed based on the structure of the template human oxidosqualene cyclase. After virtual screening technique of β-AS, a novel natural compound (8442257) has been found with the lowest affinity energy. Then we identify that Leu287 is the most important anchoring residues for binding with 8442257 because it has strong vdW interaction with inhibitor. Ser413 and Trp613 are important residues because they make hydrogen bonds with inhibitor. Our results may be helpful for further experimental investigations.

Key words: homology modeling, β-amyrin synthase, virtual screening, molecular docking