ausblenden:
Schlagwörter:
MONOTERPENOID INDOLE ALKALOIDS; PLANT-CELL CULTURES;
RAUVOLFIA-SERPENTINA; AJMALINE PATHWAY; 1ST EXAMPLE; EXPRESSION; FAMILY;
ENZYME; PURIFICATION; GLUCOSIDASEChemistry; alkaloids; biosynthesis; cytochrome p450s; perakine; vomilenine;
Zusammenfassung:
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.
