Structural determinants of reductive terpene cyclization in iridoid biosynthesis
November 9th, 2015 by Hajo Kries
Nature Chemical Biology 12, 6 (2016). doi:10.1038/nchembio.1955
Authors: Hajo Kries, Lorenzo Caputi, Clare E M Stevenson, Mohammed O Kamileen, Nathaniel H Sherden, Fernando Geu-Flores, David M Lawson & Sarah E O'Connor
The carbon skeleton of ecologically and pharmacologically important iridoid monoterpenes is formed in a reductive cyclization reaction unrelated to canonical terpene cyclization. Here we report the crystal structure of the recently discovered iridoid cyclase (from Catharanthus roseus) bound to a mechanism-inspired inhibitor that illuminates substrate binding and catalytic function of the enzyme. Key features that distinguish iridoid synthase from its close homolog progesterone 5β-reductase are highlighted.