title: Squalene cyclase and oxidosqualene cyclase from a fern.
abstract: Ferns are the most primitive vascular plants. The phytosterols of ferns are the same as those of higher plants, but they produce characteristic triterpenes. The most distinct feature is the lack of oxygen functionality at C-3, suggesting that the triterpenes of ferns may be biosynthesized by direct cyclization of squalene. To obtain some insights into the molecular bases for the biosynthesis of triterpenes in ferns, we cloned ACX, an oxidosqualene cyclase homologue, encoding a cycloartenol synthase (CAS) and ACH, a squalene cyclase homologue, encoding a 22-hydroxyhopane synthase from Adiantum capillus-veneris. Phylogenetic analysis revealed that ACH is located in the cluster of bacterial SCs, while ACX is in the cluster of higher plant CASs.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Shinozaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shibuya
authors.forename: Kazuo
authors.initials: K
authors.lastname: Masuda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ebizuka
mesh_terms: D001483:Base Sequence; D002853:Chromatography, Liquid; D003001:Cloning, Molecular; D017931:DNA Primers; D018076:DNA, Complementary; D019143:Evolution, Molecular; D008401:Gas Chromatography-Mass Spectrometry; D019751:Intramolecular Transferases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D008190:Lyases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010802:Phylogeny; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008190:Lyases; C022651:squalene cyclase; D019751:Intramolecular Transferases; C021924:lanosterol synthase