2gds
From Proteopedia
Interrupting the Hydrogen Bonding Network at the Active Site of Human Manganese Superoxide Dismutase
Structural highlights
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.[1] 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 PubMedHistidine 30 in human manganese superoxide dismutase (MnSOD) is located at a site partially exposed to solvent with its side chain participating in a hydrogen-bonded network that includes the active-site residues Tyr(166) and Tyr(34) and extends to the manganese-bound solvent molecule. We have replaced His(30) with a series of amino acids and Tyr(166) with Phe in human MnSOD. The crystal structure of the mutant of MnSOD containing Asn(30) superimposed closely with the wild type, but the side chain of Asn(30) did not participate in the hydrogen-bonded network in the active site. The catalytic activity of a number of mutants with replacements at position 30 and for the mutant containing Phe(166) showed a 10-40-fold decrease in k(cat). This is the same magnitude of decrease in k(cat) obtained with the replacement of Tyr(34) by Phe, suggesting that interrupting the hydrogen-bonded active-site network at any of the sites of these three participants (His(30), Tyr(34), and Tyr(166)) leads to an equivalent decrease in k(cat) and probably less efficient proton transfer to product peroxide. The specific geometry of His(30) on the hydrogen bond network is essential for stability since the disparate mutations H30S, H30A, and H30Q reduce T(m) by similar amounts (10-16 degrees C) compared with wild type. Interrupting the hydrogen bond network at the active site of human manganese superoxide dismutase.,Ramilo CA, Leveque V, Guan Y, Lepock JR, Tainer JA, Nick HS, Silverman DN J Biol Chem. 1999 Sep 24;274(39):27711-6. PMID:10488113[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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