5chq

Dehaloperoxidase B in complex with substrate p-nitrophenol

spinqualitylabelsall models 5chq, resolution 1.87Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5chq is a 2 chain structure with sequence from Amphitrite ornata. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.87Å Ligands: GOL, HEM, NPO, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9NAV7_9ANNE Publication Abstract from PubMed The marine hemoglobin dehaloperoxidase (DHP) from Amphitrite ornata was found to catalyze the H2O2-dependent oxidation of nitrophenols, an unprecedented nonmicrobial degradation pathway for nitrophenols by a hemoglobin. Using 4-nitrophenol (4-NP) as a representative substrate, the major monooxygenated product was 4-nitrocatechol (4-NC). Isotope labeling studies confirmed that the O atom incorporated was derived exclusively from H2O2, indicative of a peroxygenase mechanism for 4-NP oxidation. Accordingly, X-ray crystal structures of 4-NP (1.87 A) and 4-NC (1.98 A) bound to DHP revealed a binding site in close proximity to the heme cofactor. Peroxygenase activity could be initiated from either the ferric or oxyferrous states with equivalent substrate conversion and product distribution. The 4-NC product was itself a peroxidase substrate for DHP, leading to the secondary products 5-nitrobenzene-triol and hydroxy-5-nitro-1,2-benzoquinone. DHP was able to react with 2,4-dinitrophenol (2,4-DNP) but was unreactive against 2,4,6-trinitrophenol (2,4,6-TNP). pH dependence studies demonstrated increased reactivity at lower pH for both 4-NP and 2,4-DNP, suggestive of a pH effect that precludes the reaction with 2,4,6-TNP at or near physiological conditions. Stopped-flow UV-visible spectroscopic studies strongly implicate a role for Compound I in the mechanism of 4-NP oxidation. The results demonstrate that there may be a much larger number of nonmicrobial enzymes that are underrepresented when it comes to understanding the degradation of persistent organic pollutants such as nitrophenols in the environment. Nonmicrobial Nitrophenol Degradation via Peroxygenase Activity of Dehaloperoxidase-Hemoglobin from Amphitrite ornata.,McCombs NL, D'Antonio J, Barrios DA, Carey LM, Ghiladi RA Biochemistry. 2016 May 3;55(17):2465-78. doi: 10.1021/acs.biochem.6b00143. Epub, 2016 Apr 22. PMID:27070125 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Dehaloperoxidase 3D structures

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