5k90 | pdb_00005k90

Crystal structure of dimeric chlorite dismutase from Cyanothece sp. PCC7425 in complex with isothiocyanate

spinqualitylabelsall models 5k90, resolution 1.28Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5k90 is a 4 chain structure with sequence from Cyap4. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, HEM, IS8, MG, SO4 Gene: Cyan7425_1434 (CYAP4) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed The heme enzyme chlorite dismutase (Cld) catalyzes the degradation of chlorite to chloride and dioxygen. Although structure and steady-state kinetics of Clds have been elucidated, many questions remain (e.g., the mechanism of chlorite cleavage and the pH dependence of the reaction). Here, we present high-resolution X-ray crystal structures of a dimeric Cld at pH 6.5 and 8.5, its fluoride and isothiocyanate complexes and the neutron structure at pH 9.0 together with the pH dependence of the Fe(III)/Fe(II) couple, and the UV-vis and resonance Raman spectral features. We demonstrate that the distal Arg127 cannot act as proton acceptor and is fully ionized even at pH 9.0 ruling out its proposed role in dictating the pH dependence of chlorite degradation. Stopped-flow studies show that (i) Compound I and hypochlorite do not recombine and (ii) Compound II is the immediately formed redox intermediate that dominates during turnover. Homolytic cleavage of chlorite is proposed. Molecular Mechanism of Enzymatic Chlorite Detoxification: Insights from Structural and Kinetic Studies.,Schaffner I, Mlynek G, Flego N, Puhringer D, Libiseller-Egger J, Coates L, Hofbauer S, Bellei M, Furtmuller PG, Battistuzzi G, Smulevich G, Djinovic-Carugo K, Obinger C ACS Catal. 2017 Nov 3;7(11):7962-7976. doi: 10.1021/acscatal.7b01749. Epub 2017, Oct 13. PMID:29142780 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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