Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone of Aster tataricus

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• 作者：Satoru Sawai¹ ; ^a ; Hiroshi Uchiyama^a ; Syuhei Mizuno^a ; Toshio Aoki^a ; Tomoyoshi Akashi^a ; Shin-ichi Ayabe ; ^a ; ^{ayabe@brs.nihon-u.ac.jp} ; Takeyoshi Takahashi^† ; ; ^a
• 关键词：Asteraceae ; Evolution ; Oxidosqualene cyclase ; Shionone ; Triterpene ; Aster tataricus
• 刊名：FEBS Letters
• 出版年：2011
• 出版时间：6 April 2011
• 年：2011
• 卷：585
• 期：7
• 页码：1031-1036
• 全文大小：798 K

文摘

Shionone is the major triterpenoid component of Aster tataricus possessing a unique all six-membered tetracyclic skeleton and 3-oxo-4-monomethyl structure. To clarify its biosynthetic process, an oxidosqualene cyclase cDNA was isolated from A. tataricus, and the function of the enzyme was determined in lanosterol synthase-deficient yeast. The cyclase yielded ca. 90 % shionone and small amounts of β-amyrin, friedelin, dammara-20,24-dienol, and 4-epishionone and was designated as a shionone synthase (SHS). Transcripts of SHS were detected in A. tataricus organs, confirming its involvement in shionone biosynthesis. SHS was shown to have evolved in the Asteraceae from β-amyrin synthase lineages and acquired characteristic species- and product-specificities.