Dang TT, Franke J, Tatsis E, O'Connor SE. Dual Catalytic Activity of a Cytochrome P450 Controls Bifurcation at a Metabolic Branch Point of Alkaloid Biosynthesis in Rauwolfia serpentina.
Angew Chem Int Ed Engl 2017;
56:9440-9444. [PMID:
28654178 PMCID:
PMC5582599 DOI:
10.1002/anie.201705010]
[Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Indexed: 11/30/2022]
Abstract
Plants create tremendous chemical diversity from a single biosynthetic intermediate. In plant-derived ajmalan alkaloid pathways, the biosynthetic intermediate vomilenine can be transformed into the anti-arrhythmic compound ajmaline, or alternatively, can isomerize to form perakine, an alkaloid with a structurally distinct scaffold. Here we report the discovery and characterization of vinorine hydroxylase, a cytochrome P450 enzyme that hydroxylates vinorine to form vomilenine, which was found to exist as a mixture of rapidly interconverting epimers. Surprisingly, this cytochrome P450 also catalyzes the non-oxidative isomerization of the ajmaline precursor vomilenine to perakine. This unusual dual catalytic activity of vinorine hydroxylase thereby provides a control mechanism for the bifurcation of these alkaloid pathway branches. This discovery highlights the unusual catalytic functionality that has evolved in plant pathways.
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