Substrate positioning controls the partition between halogenation and hydroxylation in the aliphatic halogenase, SyrB2.

ABSTRACT: The alpha-ketoglutarate-dependent hydroxylases and halogenases employ similar reaction mechanisms involving hydrogen-abstracting Fe(IV)-oxo (ferryl) intermediates. In the halogenases, the carboxylate residue from the His(2)(Asp/Glu)(1) "facial triad" of iron ligands found in the hydroxylases is replaced by alanine, and a halide ion (X(-)) coordinates at the vacated site. Halogenation is thought to result from "rebound" of the halogen radical from the X-Fe(III)-OH intermediate produced by hydrogen (H(*)) abstraction to the substrate radical. The alternative decay pathway for the X-Fe(III)-OH intermediate, rebound of the hydroxyl radical to the substrate radical (as occurs in the hydroxylases), reportedly does not compete. Here we show for the halogenase SyrB2 that positioning of the alkyl g

SUBMITTER: Matthews ML 

PROVIDER: S-EPMC2764930 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature