A Hydrolase-Catalyzed Cyclization Forms the Fused Bicyclic beta-Lactone in Vibralactone.
Feng, K.N., Yang, Y.L., Xu, Y.X., Zhang, Y., Feng, T., Huang, S.X., Liu, J.K., Zeng, Y.(2020) Angew Chem Int Ed Engl 59: 7209-7213
- PubMed: 32050043 
- DOI: https://doi.org/10.1002/anie.202000710
- Primary Citation of Related Structures:  
6KD0 - PubMed Abstract: 
Vibralactone is isolated from the basidiomycete fungus Boreostereum vibrans as one of the strongest lipase inhibitors. Its unusual β-lactone-fused bicycle is derived from an aryl ring moiety by an oxidative ring-expansion prior to an intramolecular cyclization. Herein, we report the discovery of the cyclase VibC which belongs to the α/β-hydrolase superfamily and is involved in the vibralactone biosynthesis. Biochemical and crystal studies suggest that VibC may catalyze an aldol or an electrocyclic reaction initiated by the Ser-His-Asp catalytic triad. For the aldol and pericyclic chemistry in living cells, VibC is a unique hydrolase performing the carbocycle formation of an oxepinone to a fused bicyclic β-lactone. This presents a naturally occurring, new enzymatic reaction in both aldol and hydrolase (bio)chemistry that will guide future exploitation of these enzymes in synthetic biology for chemical-diversity expansion of natural products.
Organizational Affiliation: 
State Key Laboratory of Phytochemistry and Plant Resources in West China, Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China.