3g4x

Crystal Structure of NiSOD Y9F mutant

spinqualitylabelsall models 3g4x, resolution 2.01Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3g4x is a 3 chain structure with sequence from Streptomyces coelicolor. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.01Å Ligands: CL, NI Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SODN_STRCO 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 Superoxide dismutases rely on protein structural elements to adjust the redox potential of the metallocenter to an optimum value near 300 mV (vs NHE), to provide a source of protons for catalysis, and to control the access of anions to the active site. These aspects of the catalytic mechanism are examined herein for recombinant preparations of the nickel-dependent SOD (NiSOD) from Streptomyces coelicolor and for a series of mutants that affect a key tyrosine residue, Tyr9 (Y9F-, Y62F-, Y9F/Y62F-, and D3A-NiSOD). Structural aspects of the nickel sites are examined by a combination of EPR and X-ray absorption spectroscopies, and by single-crystal X-ray diffraction at approximately 1.9 A resolution in the case of Y9F- and D3A-NiSODs. The functional effects of the mutations are examined by kinetic studies employing pulse radiolytic generation of O2- and by redox titrations. These studies reveal that although the structure of the nickel center in NiSOD is unique, the ligand environment is designed to optimize the redox potential at 290 mV and results in the oxidation of 50% of the nickel centers in the oxidized hexamer. Kinetic investigations show that all of the mutant proteins have considerable activity. In the case of Y9F-NiSOD, the enzyme exhibits saturation behavior that is not observed in wild-type (WT) NiSOD and suggests that release of peroxide is inhibited. The crystal structure of Y9F-NiSOD reveals an anion binding site that is occupied by either Cl- or Br- and is located close to but not within bonding distance of the nickel center. The structure of D3A-NiSOD reveals that in addition to affecting the interaction between subunits, this mutation repositions Tyr9 and leads to altered chemistry with peroxide. Comparisons with Mn(SOD) and Fe(SOD) reveal that although different strategies for adjusting the redox potential and supply of protons are employed, NiSOD has evolved a similar strategy for controlling the access of anions to the active site. Role of conserved tyrosine residues in NiSOD catalysis: a case of convergent evolution.,Herbst RW, Guce A, Bryngelson PA, Higgins KA, Ryan KC, Cabelli DE, Garman SC, Maroney MJ Biochemistry. 2009 Apr 21;48(15):3354-69. PMID:19183068 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Superoxide dismutase 3D structures

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