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Publication Abstract from PubMed

The unusual diterpene (C20) synthase copalyl diphosphate synthase from Penicillium verruculosum (PvCPS) is the first bifunctional terpene synthase identified with both prenyltransferase and class II cyclase activities in a single polypeptide chain with alphabetagamma domain architecture. The C-terminal prenyltransferase alphadomain generates geranylgeranyl diphosphate which is then cyclized to form copalyl diphosphate at the N-terminal betagamma domain interface. We now demonstrate that PvCPS exists as a hexamer at high concentrations - a unique quaternary structure for known alphabetagamma terpene synthases. Hexamer assembly is corroborated by a 2.41 A-resolution crystal structure of the alpha domain prenyltransferase obtained from limited proteolysis of full-length PvCPS, as well as the ab initio modeling of full-length PvCPS derived from small-angle X-ray scattering data. Hexamerization of the prenyltransferase alphadomain appears to drive the hexamerization of full-length PvCPS. The PvCPS hexamer dissociates into lower-order species at lower concentrations, as evidenced by size-exclusion chromatography in-line with multiangle light scattering, sedimentation velocity analytical ultracentrifugation, and native polyacrylamide gel electrophoresis experiments, suggesting that oligomerization is concentration dependent. Even so, PvCPS oligomer assembly does not affect prenyltransferase activity in vitro.

Higher-Order Oligomerization of a Chimeric alphabetagamma Bifunctional Diterpene Synthase with Prenyltransferase and Class II Cyclase Activities is Concentration-Dependent.,Ronnebaum TA, Gupta K, Christianson DW J Struct Biol. 2020 Jan 21:107463. doi: 10.1016/j.jsb.2020.107463. PMID:31978464^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.