title: β-Amyrin biosynthesis: the critical role of steric volume at C-19 of 2,3-oxidosqualene for its correct folding to generate the pentacyclic scaffold.
abstract: The effect of the steric volume at C-19 of (3S)-2,3-oxidosqualene 1 on the polycyclization reaction by β-amyrin synthase was examined. The substrate analogs, in which the methyl group at C-19 of 1 was substituted by an ethyl group and hydrogen atom, were converted into the following three new compounds: (17β-H, 20S)-20-ethyl-dammara-12,24-diene 9, β-amyrin homologue 10, and the 6,6,6,6-fused tetracycle 11. The folding conformations leading to these products are discussed.
authors: Graduate School of Science and Technology, and Department of Applied Biological Chemistry, Faculty of Agriculture, Niigata University , Ikarashi 2-8050, Nishi-ku, Niigata 950-2181, Japan.
authors: Tsutomu
authors: T
authors: Hoshino
authors: Yuki
authors: Y
authors: Yamaguchi
authors: Kazunari
authors: K
authors: Takahashi
authors: Ryousuke
authors: R
authors: Ito
mesh_terms: D003500:Cyclization; D019751:Intramolecular Transferases / Q000378:metabolism; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D009828:Oleanolic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000737:chemistry; D013185:Squalene / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: C002821:2,3-oxidosqualene; C520393:oxidosqualene; D009828:Oleanolic Acid; D013185:Squalene; D019751:Intramolecular Transferases; C039924:2,3-oxidosqualene-beta-amyrin-cyclase; C036380:beta-amyrin