1qi9

X-RAY SIRAS STRUCTURE DETERMINATION OF A VANADIUM-DEPENDENT HALOPEROXIDASE FROM ASCOPHYLLUM NODOSUM AT 2.0 A RESOLUTION

spinqualitylabelsall models 1qi9, resolution 2.05Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1qi9 is a 2 chain structure with sequence from Ascophyllum nodosum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.05Å Ligands: IYR, PCA, TYI, VO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PRXV_ASCNO Catalyzes the halogenation of organic substrates in the presence of hydrogen peroxide. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The homo-dimeric structure of a vanadium-dependent haloperoxidase (V-BPO) from the brown alga Ascophyllum nodosum (EC 1.1.11.X) has been solved by single isomorphous replacement anomalous scattering (SIRAS) X-ray crystallography at 2.0 A resolution (PDB accession code 1QI9), using two heavy-atom datasets of a tungstate derivative measured at two different wavelengths. The protein sequence (SwissProt entry code P81701) of V-BPO was established by combining results from protein and DNA sequencing, and electron density interpretation. The enzyme has nearly an all-helical structure, with two four-helix bundles and only three small beta-sheets. The holoenzyme contains trigonal-bipyramidal coordinated vanadium atoms at its two active centres. Structural similarity to the only other structurally characterized vanadium-dependent chloroperoxidase (V-CPO) from Curvularia inaequalis exists in the vicinity of the active site and to a lesser extent in the central four-helix bundle. Despite the low sequence and structural similarity between V-BPO and V-CPO, the vanadium binding centres are highly conserved on the N-terminal side of an alpha-helix and include the proposed catalytic histidine residue (His418(V-BPO)/His404(V-CPO)). The V-BPO structure contains, in addition, a second histidine near the active site (His411(V-BPO)), which can alter the redox potential of the catalytically active VO2-O2 species by protonation/deprotonation reactions. Specific binding sites for the organic substrates, like indoles and monochlordimedone, or for halide ions are not visible in the V-BPO structure. A reaction mechanism for the enzymatic oxidation of halides is discussed, based on the present structural, spectroscopic and biochemical knowledge of vanadium-dependent haloperoxidases, explaining the observed enzymatic differences between both enzymes. X-ray structure determination of a vanadium-dependent haloperoxidase from Ascophyllum nodosum at 2.0 A resolution.,Weyand M, Hecht H, Kiess M, Liaud M, Vilter H, Schomburg D J Mol Biol. 1999 Oct 29;293(3):595-611. PMID:10543953 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Haloperoxidase

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