title: Dammarenediol-II synthase, the first dedicated enzyme for ginsenoside biosynthesis, in Panax ginseng.
abstract: Panax ginseng produces triterpene saponins called ginsenosides, which are classified into two groups by the skeleton of aglycones, namely dammarane type and oleanane type. Dammarane-type ginsenosides dominate over oleanane type not only in amount but also in structural varieties. However, their sapogenin structure is restricted to two aglycones, protopanaxadiol and protopanaxatriol. So far, the genes encoding oxidosqualene cyclase (OSC) responsible for formation of dammarane skeleton have not been cloned, although OSC yielding oleanane skeleton (beta-amyrin synthase) has been successfully cloned from this plant. In this study, cDNA cloning of OSC producing dammmarane triterpene was attempted from hairy root cultures of P. ginseng by homology based PCR method. A new OSC gene (named as PNA) obtained was expressed in a lanosterol synthase deficient (erg7) Saccharomyces cerevisiae strain GIL77. LC-MS and NMR analyses identified the accumulated product in the yeast transformant to be dammarenediol-II, demonstrating PNA to encode dammarenediol-II synthase.
authors.affiliation: Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan.
authors.forename: Pimpimon
authors.initials: P
authors.lastname: Tansakul
authors.forename: Masaaki
authors.initials: M
authors.lastname: Shibuya
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Kushiro
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Ebizuka
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000737:chemistry*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D015870:Gene Expression; D036145:Ginsenosides / Q000096:biosynthesis / Q000235:genetics*; D008025:Ligases / Q000096:biosynthesis / Q000235:genetics*; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D005894:Panax / Q000201:enzymology / Q000235:genetics*; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014315:Triterpenes / Q000378:metabolism; D000097669:Dammaranes
chemical_list: D019883:Alkyl and Aryl Transferases; D018076:DNA, Complementary; D036145:Ginsenosides; D008025:Ligases; D009828:Oleanolic Acid; D010940:Plant Proteins; D011994:Recombinant Proteins; D014315:Triterpenes; D000097669:Dammaranes; C413246:oleanane; C514651:dammarenediol-II synthase, Panax ginseng