title: Stereochemical course in water addition during LUP1-catalyzed triterpene cyclization.
abstract: Arabidopsis thaliana LUP1 (At1g78970) catalyzes the cyclization of oxidosqualene into lupeol and 3beta,20-dihydroxylupane (lupanediol). The stereochemical course of water addition to the lupanyl cation was studied. The X-ray crystal structure of lupanylepoxide 3,5-dinitrobenzoate established the configuration of epoxide as 20S. LiAlD4 reduction of the epoxide enabled the chemical shift assignment of prochiral methyl groups at C20 of lupanediol. Correlation of these methyl groups with biosynthetic lupanediol from [1,2-(13)C(2)] acetate established the stereochemical course of water addition. [reaction: see text].
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kushiro
authors.forename: Masaki
authors.initials: M
authors.lastname: Hoshino
authors.forename: Takehiko
authors.initials: T
authors.lastname: Tsutsumi
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kawai
authors.forename: Motoo
authors.initials: M
authors.lastname: Shiro
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shibuya
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ebizuka
mesh_terms: D029681:Arabidopsis Proteins / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D019751:Intramolecular Transferases / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014315:Triterpenes / Q000138:chemical synthesis*; D014867:Water / Q000737:chemistry
chemical_list: D029681:Arabidopsis Proteins; D014315:Triterpenes; D014867:Water; D019751:Intramolecular Transferases; C522754:LUP1 protein, Arabidopsis; C021924:lanosterol synthase