Crystal structures of α-dioxygenase from Oryza sativa: insights into substrate binding and activation by hydrogen peroxide.

ABSTRACT: α-Dioxygenases (α-DOX) are heme-containing enzymes found predominantly in plants and fungi, where they generate oxylipins in response to pathogen attack. α-DOX oxygenate a variety of 14-20 carbon fatty acids containing up to three unsaturated bonds through stereoselective removal of the pro-R hydrogen from the α-carbon by a tyrosyl radical generated via the oxidation of the heme moiety by hydrogen peroxide (H2 O2 ). We determined the X-ray crystal structures of wild type α-DOX from Oryza sativa, the wild type enzyme in complex with H2 O2 , and the catalytically inactive Y379F mutant in complex with the fatty acid palmitic acid (PA). PA binds within the active site cleft of α-DOX such that the carboxylate forms ionic interactions with His-311 and Arg-559. Thr-316 aids in the positioning of

SUBMITTER: Zhu G 

PROVIDER: S-EPMC3795501 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature