6alp
From Proteopedia
VioC L-arginine hydroxylase bound to Fe(II), 3S-hydroxy-L-arginine, and succinate
Structural highlights
Function[ARGHX_STRVI] Involved in the biosynthesis of capreomycidine, an unusual amino acid used by non-ribosomal peptide synthases (NRPS) to make the tuberactinomycin class of peptide antibiotics such as viomycin and capreomycin. Catalyzes the stereospecific hydroxylation of the C3 of (2S)-arginine to generate (3S)-hydroxy-(2S)-arginine. Usually clavaminic acid synthase-like oxygenases catalyze the formation of threo diastereomers, however VioC produces the erythro diastereomer of beta-carbon-hydroxylated L-arginine. It exerts a broad substrate specificity by accepting the analogs L-homoarginine and L-canavanine for the beta-carbon hydroxylation.[1] [2] [3] Publication Abstract from PubMedIron(II)- and 2-(oxo)-glutarate-dependent oxygenases catalyze diverse oxidative transformations that are often initiated by abstraction of hydrogen from carbon by iron(IV)-oxo (ferryl) complexes. Control of the relative orientation of the substrate C-H and ferryl Fe-O bonds, primarily by direction of the oxo group into one of two cis-related coordination sites (termed inline and offline), may be generally important for control of the reaction outcome. Neither the ferryl complexes nor their fleeting precursors have been crystallographically characterized, hindering direct experimental validation of the offline hypothesis and elucidation of the means by which the protein might dictate an alternative oxo position. Comparison of high-resolution x-ray crystal structures of the substrate complex, an Fe(II)-peroxysuccinate ferryl precursor, and a vanadium(IV)-oxo mimic of the ferryl intermediate in the L-arginine 3-hydroxylase, VioC, reveals coordinated motions of active site residues that appear to control the intermediate geometries to determine reaction outcome. Visualizing the reaction cycle in an iron(II)- and 2-(oxo)-glutarate-dependent hydroxylase.,Mitchell AJ, Dunham NP, Martinie RJ, Bergman JA, Pollock CJ, Hu K, Allen BD, Chang WC, Silakov A, Bollinger JM Jr, Krebs C, Boal AK J Am Chem Soc. 2017 Aug 20. doi: 10.1021/jacs.7b07374. PMID:28823155[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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