1eqw
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CRYSTAL STRUCTURE OF SALMONELLA TYPHIMURIUM CU,ZN SUPEROXIDE DISMUTASE
OverviewOverview
The functional and three-dimensional structural features of Cu,Zn, superoxide dismutase coded by the Salmonella typhimurium sodCI gene, have, been characterized. Measurements of the catalytic rate indicate that this, enzyme is the most efficient superoxide dismutase analyzed so far, a, feature that may be related to the exclusive association of the sodCI gene, with the most pathogenic Salmonella serotypes. The enzyme active-site, copper ion is highly accessible to external probes, as indicated by, quenching of the water proton relaxation rate upon addition of iodide. The, shape of the electron paramagnetic resonance spectrum is dependent on the, frozen or liquid state of the enzyme solution, suggesting relative, flexibility of the copper ion environment. The crystal structure (R-factor, 22.6%, at 2.3 A resolution) indicates that the dimeric enzyme adopts the, quaternary assembly typical of prokaryotic Cu,Zn superoxide dismutases., However, when compared to the structures of the homologous enzymes from, Photobacterium leiognathi and Actinobacillus pleuropneumoniae, the subunit, interface of Salmonella Cu,Zn superoxide dismutase shows substitution of, 11 out of 19 interface residues. As a consequence, the network of, structural water molecules that fill the dimer interface cavity is, structured differently from the other dimeric bacterial enzymes. The, crystallographic and functional characterization of this Salmonella Cu,Zn, superoxide dismutase indicates that structural variability and catalytic, efficiency are higher in prokaryotic than in the eukaryotic homologous, enzymes.
About this StructureAbout this Structure
1EQW is a Single protein structure of sequence from Salmonella typhimurium with ZN and CU as ligands. Active as Superoxide dismutase, with EC number 1.15.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Functional and crystallographic characterization of Salmonella typhimurium Cu,Zn superoxide dismutase coded by the sodCI virulence gene., Pesce A, Battistoni A, Stroppolo ME, Polizio F, Nardini M, Kroll JS, Langford PR, O'Neill P, Sette M, Desideri A, Bolognesi M, J Mol Biol. 2000 Sep 15;302(2):465-78. PMID:10970746
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