1zuq

Contribution to Structure and Catalysis of Tyrosine 34 in Human Manganese Superoxide Dismutase

spinqualitylabelsall models 1zuq, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1zuq is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: MN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease SODM_HUMAN Genetic variation in SOD2 is associated with susceptibility to microvascular complications of diabetes type 6 (MVCD6) [MIM:612634. These are pathological conditions that develop in numerous tissues and organs as a consequence of diabetes mellitus. They include diabetic retinopathy, diabetic nephropathy leading to end-stage renal disease, and diabetic neuropathy. Diabetic retinopathy remains the major cause of new-onset blindness among diabetic adults. It is characterized by vascular permeability and increased tissue ischemia and angiogenesis. Function SODM_HUMAN 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 Superoxide dismutase (SOD) enzymes are critical in controlling levels of reactive oxygen species (ROS) that are linked to aging, cancer, and neurodegenerative disease. Superoxide (O(2)(*-)) produced during respiration is removed by the product of the SOD2 gene, the homotetrameric manganese superoxide dismutase (MnSOD). Here, we examine the structural and catalytic roles of the highly conserved active-site residue Tyr34, based upon structure-function studies of MnSOD enzymes with mutations at this site. Substitution of Tyr34 with five different amino acids retained the active-site protein structure and assembly but caused a substantial decrease in the catalytic rate constant for the reduction of superoxide. The rate constant for formation of the product inhibition complex also decreases but to a much lesser extent, resulting in a net increase in the level of product inhibited form of the mutant enzymes. Comparisons of crystal structures and catalytic rates also suggest that one mutation, Y34V, interrupts the hydrogen-bonded network, which is associated with a rapid dissociation of the product-inhibited complex. Notably, with three of the Tyr34 mutants, we also observe an intermediate in catalysis, which has not been reported previously. Thus, these mutants establish a means of trapping a catalytic intermediate that promises to help elucidate the mechanism of catalysis. Contribution of Human Manganese Superoxide Dismutase Tyrosine 34 to Structure and Catalysis (dagger).,Perry JJ, Hearn AS, Cabelli DE, Nick HS, Tainer JA, Silverman DN Biochemistry. 2009 Mar 27. PMID:19265433 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Superoxide dismutase 3D structures

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