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Differential Stereocontrolled Formation of Tricyclic Triterpenes by Mutation of Tyrosine 99 of the Oxidosqualene‐Lanosterol Cyclase from Saccharomyces cerevisiae
Author(s) -
Wu TungKung,
Li WenHsuan,
Chang ChengHsiang,
Wen HaoYu,
Liu YuanTing,
Chang YiChun
Publication year - 2009
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200900638
Subject(s) - chemistry , lanosterol , stereochemistry , saccharomyces cerevisiae , deprotonation , cyclase , terpene , tricyclic , mutant , biochemistry , yeast , organic chemistry , sterol , enzyme , gene , ion , cholesterol
The function of the Tyr99 residue from Saccharomyces cerevisiae oxidosqualene‐lanosterol cyclase (ERG7) was analyzed by constructing deletion and site‐saturated mutants. Two truncated intermediates, (13α H )‐isomalabarica‐14 Z ,17 E ,21‐trien‐3β‐ol and (13α H )‐isomalabarica‐14 E ,17 E ,21‐trien‐3β‐ol, were isolated from the ERG7 Y99X mutants. These results suggest that the functional role of ERG7 Y99 is to affect both chair–boat 6–6–5 tricyclic Markovnikov C‐14 cation stabilization and thestereochemistry of the protons at the C‐15 position for subsequent deprotonation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)