Structural insight on assembly-line catalysis in terpene biosynthesis.
Faylo, J.L., van Eeuwen, T., Kim, H.J., Gorbea Colon, J.J., Garcia, B.A., Murakami, K., Christianson, D.W.(2021) Nat Commun 12: 3487-3487
- PubMed: 34108468 
- DOI: https://doi.org/10.1038/s41467-021-23589-9
- Primary Citation of Related Structures:  
7JTH - PubMed Abstract: 
Fusicoccadiene synthase from Phomopsis amygdali (PaFS) is a unique bifunctional terpenoid synthase that catalyzes the first two steps in the biosynthesis of the diterpene glycoside Fusicoccin A, a mediator of 14-3-3 protein interactions. The prenyltransferase domain of PaFS generates geranylgeranyl diphosphate, which the cyclase domain then utilizes to generate fusicoccadiene, the tricyclic hydrocarbon skeleton of Fusicoccin A. Here, we use cryo-electron microscopy to show that the structure of full-length PaFS consists of a central octameric core of prenyltransferase domains, with the eight cyclase domains radiating outward via flexible linker segments in variable splayed-out positions. Cryo-electron microscopy and chemical crosslinking experiments additionally show that compact conformations can be achieved in which cyclase domains are more closely associated with the prenyltransferase core. This structural analysis provides a framework for understanding substrate channeling, since most of the geranylgeranyl diphosphate generated by the prenyltransferase domains remains on the enzyme for cyclization to form fusicoccadiene.
Organizational Affiliation: 
Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, United States.