4okz
Selinadiene Synthase in complex with dihydrofarnesyl pyrophosphate
Structural highlights
FunctionSEDS_STRE2 Catalyzes the conversion of (2E,6E)-farnesyl diphosphate (FPP) to yield the bicyclic sesquiterpene selina-4(15),7(11)-diene via a 1,10-cyclization, which requires the abstraction of the pyrophosphate from FPP leading to a (E,E)-germacradienyl cation (PubMed:23307484, PubMed:24890698). The only accepted substrate is (2E,6E)-farnesyl diphosphate (FPP) (PubMed:23307484, PubMed:24890698).[1] [2] Publication Abstract from PubMedWe present crystallographic and functional data of selina-4(15),7(11)-diene synthase (SdS) from Streptomyces pristinaespiralis in its open and closed (ligand-bound) conformation. We could identify an induced-fit mechanism by elucidating a rearrangement of the G1/2 helix-break motif upon substrate binding. This rearrangement highlights a novel effector triad comprising the pyrophosphate sensor Arg178, the linker Asp181, and the effector Gly182-O. This structural motif is strictly conserved in class I terpene cyclases from bacteria, fungi, and plants, including epi-isozizaene synthase (3KB9), aristolochene synthase (4KUX), bornyl diphosphate synthase (1N20), limonene synthase (2ONG), 5-epi-aristolochene synthase (5EAT), and taxa-4(5),11(12)-diene synthase (3P5R). An elaborate structure-based mutagenesis in combination with analysis of the distinct product spectra confirmed the mechanistic models of carbocation formation and stabilization in SdS. Induced-Fit Mechanism in Class I Terpene Cyclases.,Baer P, Rabe P, Fischer K, Citron CA, Klapschinski TA, Groll M, Dickschat JS Angew Chem Int Ed Engl. 2014 May 30. doi: 10.1002/anie.201403648. PMID:24890698[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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