The biosynthesis of iridoids, a class of bicyclic monoterpenes, features an atypical cyclization reaction catalyzed by iridoid synthase (ISY). Crystallographic and biochemical characterization of ISY from Catharanthus roseus provides insights into the ISY enzymatic mechanism and highlights similarities with the homologous progesterone 5β-reductase. Credit: The John Innes Centre
Scientists identify 3D structure of enzyme critical to the creation of anticancer and antimalarial compounds in plants
In a paper published today in Nature Chemical Biology, Professor Sarah O'Connor and Dr Dave Lawson have identified, for the first time, the 3D structure of the enzyme iridoid synthase responsible for a very specific form of cyclisation of monoterpenes which creates anticancer and antimalarial drugs.
The enzyme iridoid synthase plays a crucial role in the biosynthesis of a large class of plant natural products, the iridoids. Iridoids are the starting precursors for a large group of products such as the anticancer agent vinblastine, the antimalarial quinine and the active ingredient of catnip. Iridoid synthase generates the core of iridoid natural products by cyclizing a monoterpene precursor in a mode that is fundamentally different from other enzymes acting on monoterpenes.
The first gene of an iridoid synthase has only recently been discovered. In their paper they report the three-D structure of this enzyme which provides more detailed information on the mechanism of iridoid synthase.
More information: Structural determinants of reductive terpene cyclization in iridoid biosynthesis, Nature Chemical Biology,
Journal information: Nature Chemical Biology
Provided by John Innes Centre
