Characterization of Micromonocyclol Synthase from the Marine Actinomycete Micromonospora marina

As a member of a large phylogenetic Glade of enzymes in Micromonospora, a terpene synthase from M. marina is functionally characterized to produce micromonocyclol. This diterpene alcohol features a rare 15-membered ring, which prevented elucidation of the only stereocenter by labeling experiments. This problem was addressed by chemical transformation into bicyclic brominated derivatives, whose rigidified skeletons allowed for a stereochemical assignment. Using this strategy, a complete stereochemical model of the cyclization mechanism was also elaborated.