1haw
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X-RAY STRUCTURE OF A BLUE COPPER NITRITE REDUCTASE AT HIGH PH AND IN COPPER FREE FORM AT 1.9A RESOLUTION
OverviewOverview
Copper-containing nitrite reductases possess a trimeric structure where, the catalytic Cu site, located at the monomer-monomer interface, resembles, the catalytic sites of a number of Zn enzymes. Nitrite reductase from, Alcaligenes xylosoxidans has optimum activity at pH 5.2 which decreases to, a negligible level at pH 8. The structure of this nitrite reductase has, previously been determined at pH 4.6. It has now been crystallized under, new conditions at pH 8.5. Its crystallographic structure provides a, structural explanation for the greatly reduced activity of the enzyme at, high pH. Characterization of overexpressed protein in solution by EXAFS, suggested that the protein lacked Cu in the catalytic type 2 Cu site and, that the site was most probably occupied by Zn. Using the anomalous, signals from Cu and Zn, the crystal structure revealed that the expressed, protein was devoid of Cu in the catalytic site and that only a trace, amount (<10%) of Zn was present at this site in the crystal. Despite the, close structural similarity of the catalytic site to a number of Zn, enzymes, these data suggest that Zn, if it binds at the catalytic copper, site, binds weakly in nitrite reductase.
About this StructureAbout this Structure
1HAW is a Single protein structure of sequence from Achromobacter xylosoxidans with as ligand. Active as Transferred entry: 1.7.2.1, with EC number 1.7.99.3 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
ReferenceReference
X-ray structure of a blue copper nitrite reductase at high pH and in copper-free form at 1.9 A resolution., Ellis MJ, Dodd FE, Strange RW, Prudencio M, Sawers G, Eady RR, Hasnain SS, Acta Crystallogr D Biol Crystallogr. 2001 Aug;57(Pt 8):1110-8. Epub 2001, Jul 23. PMID:11468394
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