3k9s | pdb_00003k9s

Crystal structure of the peroxide-bound manganese superoxide dismutase.

spinqualitylabelsall models 3k9s, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3k9s is a 4 chain structure with sequence from Ecoli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MN, PEO Gene: b3908, JW3879, sodA (ECOLI) Activity: Superoxide dismutase, with EC number 1.15.1.1 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SODM_ECOLI] Destroys superoxide anion radicals which are normally produced within the cells and which are toxic to biological systems. 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 superoxide dismutase (SOD) enzymes are important antioxidant agents that protect cells from reactive oxygen species. The SOD family is responsible for catalyzing the disproportionation of superoxide radical to oxygen and hydrogen peroxide. Manganese- and iron-containing SOD exhibit product inhibition whereas Cu/ZnSOD does not. Here, we report the crystal structure of Escherichia coli MnSOD with hydrogen peroxide cryotrapped in the active site. Crystallographic refinement to 1.55 A and close inspection revealed electron density for hydrogen peroxide in three of the four active sites in the asymmetric unit. The hydrogen peroxide molecules are in the position opposite His26 that is normally assumed by water in the trigonal bipyramidal resting state of the enzyme. Hydrogen peroxide is present in active sites B, C, and D and is side-on coordinated to the active-site manganese. In chains B and D, the peroxide is oriented in the plane formed by manganese and ligands Asp167 and His26. In chain C, the peroxide is bound, making a 70 degrees angle to the plane. Comparison of the peroxide-bound active site with the hydroxide-bound octahedral form shows a shifting of residue Tyr34 towards the active site when peroxide is bound. Comparison with peroxide-soaked Cu/ZnSOD indicates end-on binding of peroxide when the SOD does not exhibit inhibition by peroxide and side-on binding of peroxide in the product-inhibited state of MnSOD. Structural analysis of peroxide-soaked MnSOD crystals reveals side-on binding of peroxide to active-site manganese.,Porta J, Vahedi-Faridi A, Borgstahl GE J Mol Biol. 2010 Jun 11;399(3):377-84. Epub 2010 Apr 24. PMID:20417642 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Superoxide Dismutase

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