title: Triterpene functional genomics in licorice for identification of CYP72A154 involved in the biosynthesis of glycyrrhizin.
abstract: Glycyrrhizin, a triterpenoid saponin derived from the underground parts of Glycyrrhiza plants (licorice), has several pharmacological activities and is also used worldwide as a natural sweetener. The biosynthesis of glycyrrhizin involves the initial cyclization of 2,3-oxidosqualene to the triterpene skeleton β-amyrin, followed by a series of oxidative reactions at positions C-11 and C-30, and glycosyl transfers to the C-3 hydroxyl group. We previously reported the identification of a cytochrome P450 monooxygenase (P450) gene encoding β-amyrin 11-oxidase (CYP88D6) as the initial P450 gene in glycyrrhizin biosynthesis. In this study, a second relevant P450 (CYP72A154) was identified and shown to be responsible for C-30 oxidation in the glycyrrhizin pathway. CYP72A154 expressed in an engineered yeast strain that endogenously produces 11-oxo-β-amyrin (a possible biosynthetic intermediate between β-amyrin and glycyrrhizin) catalyzed three sequential oxidation steps at C-30 of 11-oxo-β-amyrin supplied in situ to produce glycyrrhetinic acid, a glycyrrhizin aglycone. Furthermore, CYP72A63 of Medicago truncatula, which has high sequence similarity to CYP72A154, was able to catalyze C-30 oxidation of β-amyrin. These results reveal a function of CYP72A subfamily proteins as triterpene-oxidizing enzymes and provide a genetic tool for engineering the production of glycyrrhizin.
authors: Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan.
authors: Hikaru
authors: H
authors: Seki
authors: Satoru
authors: S
authors: Sawai
authors: Kiyoshi
authors: K
authors: Ohyama
authors: Masaharu
authors: M
authors: Mizutani
authors: Toshiyuki
authors: T
authors: Ohnishi
authors: Hiroshi
authors: H
authors: Sudo
authors: Ery Odette
authors: EO
authors: Fukushima
authors: Tomoyoshi
authors: T
authors: Akashi
authors: Toshio
authors: T
authors: Aoki
authors: Kazuki
authors: K
authors: Saito
authors: Toshiya
authors: T
authors: Muranaka
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D006034:Glycyrrhetinic Acid / Q000378:metabolism; D006035:Glycyrrhiza / Q000235:genetics* / Q000378:metabolism*; D019695:Glycyrrhizic Acid / Q000378:metabolism*; D046913:Medicago truncatula / Q000201:enzymology; D008969:Molecular Sequence Data; D009828:Oleanolic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D014315:Triterpenes / Q000378:metabolism*; D015003:Yeasts / Q000235:genetics
chemical_list: D014315:Triterpenes; D019695:Glycyrrhizic Acid; D009828:Oleanolic Acid; D003577:Cytochrome P-450 Enzyme System; C036380:beta-amyrin; D006034:Glycyrrhetinic Acid