@article {45763,
	title = {Cyclization mechanism of phomopsene synthase: mass spectrometry based analysis of various site-specifically labeled terpenes},
	journal = {Journal of Antibiotics},
	volume = {70},
	year = {2017},
	month = {MAY},
	pages = {632-638},
	type = {Article},
	abstract = {<p>Elucidation of the cyclization mechanism catalyzed by terpene synthases is important for the rational engineering of terpene cyclases. We developed a chemoenzymatic method for the synthesis of systematically deuterium-labeled geranylgeranyl diphosphate ( GGPP), starting from site-specifically deuterium-labeled isopentenyl diphosphates (IPPs) using IPP isomerase and three prenyltransferases. We examined the cyclization mechanism of tetracyclic diterpene phomopsene with phomopsene synthase. A detailed EI-MS analysis of phomopsene labeled at various positions allowed us to propose the structures corresponding to the most intense peaks, and thus elucidate a cyclization mechanism involving double 1,2-alkyl shifts and a 1,2-hydride shift via a dolabelladien-15-yl cation. Our study demonstrated that this newly developed method is highly sensitive and provides sufficient information for a reliable assignment of the structures of fragmented ions.</p>},
	issn = {0021-8820},
	doi = {10.1038/ja.2017.27},
	author = {Shinde, Sandip S. and Minami, Atsushi and Chen, Zhi and Tokiwano, Tetsuo and Toyomasu, Tomonobu and Kato, Nobuo and Sassa, Takeshi and Oikawa, Hideaki}
}
