title: Directed evolution experiments reveal mutations at cycloartenol synthase residue His477 that dramatically alter catalysis.
abstract: [reaction: see text] Cycloartenol synthase cyclizes and rearranges oxidosqualene to the protosteryl cation and then specifically deprotonates from C-19. To identify mutants that deprotonate differently, randomly generated mutant cycloartenol synthases were selected in a yeast lanosterol synthase mutant. A novel His477Asn mutant was uncovered that produces 88% lanosterol and 12% parkeol. The His477Gln mutant produces 73% parkeol, 22% lanosterol, and 5% Delta(7)-lanosterol. These are the most accurate lanosterol synthase and parkeol synthase that have been generated by mutagenesis.
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Michael J R
authors.initials: MJ
authors.lastname: Segura
authors.forename: Silvia
authors.initials: S
authors.lastname: Lodeiro
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Meyer
authors.forename: Akash J
authors.initials: AJ
authors.lastname: Patel
authors.forename: Seiichi P T
authors.initials: SP
authors.lastname: Matsuda
mesh_terms: D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000235:genetics; D002384:Catalysis; D017124:Conserved Sequence; D019020:Directed Molecular Evolution; D018698:Glutamic Acid / Q000235:genetics; D006639:Histidine / Q000235:genetics* / Q000378:metabolism*; D019751:Intramolecular Transferases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation / Q000235:genetics*; D013329:Structure-Activity Relationship; D015003:Yeasts / Q000201:enzymology / Q000235:genetics
chemical_list: D007810:Lanosterol; C093882:parkeol; D001224:Aspartic Acid; D018698:Glutamic Acid; D006639:Histidine; D019751:Intramolecular Transferases; C021924:lanosterol synthase; C021923:cycloartenol synthase