Structural Basis for the Erythro-Stereospecificity of the L-Arginine Oxygenase Vioc in Viomycin Biosynthesis.

摘要: The nonheme iron oxygenase VioC from Streptomyces vinaceus catalyzes Fe(II)-dependent and alpha-ketoglutarate-dependent Cbeta-hydroxylation of L-arginine during the biosynthesis tuberactinomycin antibiotic viomycin. Crystal structures were determined in complexes with cofactor Fe(II), substrate L-arginine, product (2S,3S)-hydroxyarginine coproduct succinate at 1.1-1.3 A resolution. overall structure reveals a beta-helix core fold two additional helical subdomains that are common to oxygenases clavaminic acid synthase-like superfamily. In contrast other oxygenases, which catalyze formation threo diastereomers, produces erythro diastereomer Cbeta-hydroxylated L-arginine. This unexpected stereospecificity is caused by conformational control bound substrate, enforces gauche(-) conformer for chi(1) instead trans conformers observed asparagine AsnO members Additionally, specificity was investigated. side chain projects outwards active site undergoing interactions mainly C-terminal subdomain. Accordingly, exerts broadened accepting analogs L-homoarginine L-canavanine Cbeta-hydroxylation.