title: Arabidopsis camelliol C synthase evolved from enzymes that make pentacycles.
abstract: We establish by heterologous expression that the Arabidopsis thaliana oxidosqualene cyclase At1g78955 (CAMS1) makes camelliol C (98%), achilleol A (2%), and beta-amyrin (0.2%). CAMS1 is the first characterized cyclase that generates predominantly a monocyclic triterpene alcohol. Phylogenetic analysis shows that CAMS1 evolved from enzymes that make pentacycles, thus revealing that its pentacyclic beta-amyrin byproduct is an evolutionary relic. Sequence alignments support prior suggestions that decreased steric bulk at a key active-site residue promotes monocycle formation.
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Mariya D
authors.initials: MD
authors.lastname: Kolesnikova
authors.forename: William K
authors.initials: WK
authors.lastname: Wilson
authors.forename: David A
authors.initials: DA
authors.lastname: Lynch
authors.forename: Allie C
authors.initials: AC
authors.lastname: Obermeyer
authors.forename: Seiichi P T
authors.initials: SP
authors.lastname: Matsuda
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D008401:Gas Chromatography-Mass Spectrometry; D006571:Heterocyclic Compounds / Q000737:chemistry* / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010802:Phylogeny; D016415:Sequence Alignment; D014315:Triterpenes / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D006571:Heterocyclic Compounds; D014315:Triterpenes; C526093:camelliol C