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Molecular characterization of an oxidosqualene cyclase that yields shionone, a unique tetracyclic triterpene ketone of Aster tataricus
Author(s) -
Sawai Satoru,
Uchiyama Hiroshi,
Mizuno Syuhei,
Aoki Toshio,
Akashi Tomoyoshi,
Ayabe Shin-ichi,
Takahashi Takeyoshi
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.02.037
Subject(s) - cyclase , stereochemistry , atp synthase , triterpene , biology , biosynthesis , biochemistry , diterpene , enzyme , chemistry , medicine , alternative medicine , pathology
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.