hide
Free keywords:
-
Abstract:
Promiscuity of terpene synthases results in the enormous diversity of terpenes found in nature.
Multiproduct sesquiterpene synthase MtTPS5 isolated from Medicago truncatula generates 27 optically
pure products from its natural substrate (2E,6E)-farnesyl diphosphate (FDP). In order to study the
promiscuity of MtTPS5, (2Z,6E)-FDP an analogue of presumptive reaction intermediates from natural
reaction cascade was utilized as a substrate. This stereoisomer induced a novel cyclization pathway
leading to sesquiterpenes based on humulane, amorphene and himachalane skeletons. Interestingly,
none of these products matched with those observed on incubation of MtTPS5 with natural (2E,6E)-
FDP. Further determination of absolute configuration of each product helped rebuild the stereochemical
route of the reaction cascade. Interestingly, the presence of only one enantiomer of each product was
observed indicating the highly stereospecific nature of the enzymatic reaction. Substrate promiscuity of
terpene synthases provides organism access to novel chemical bouquets of high optical purity by
utilizing existing enzymes. Presence of this mechanism was indicated by the presence of these alternate products in natural herbivore-induced volatiles of Medicago truncatula.
