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==Overview== | ==Overview== | ||
Copper-containing nitrite reductases (NiR's) have been conveniently, subdivided into blue and green NiR's which are thought to be redox, partners of azurins and pseudo-azurins, respectively. Crystal structures, of two green NiR's have recently been determined. Alcaligenes xylosoxidans, has been shown to have a blue-copper nitrite reductase (AxNiR) and two, azurins with 67% homology both of which donate electrons to it, effectively. The first crystal structure of a blue NiR (AxNiR) in its, oxidized and nitrite-bound forms, with particular emphasis to the Cu, sites, is presented. The Cu-Smet distance is the same as those in the, green NiR's. Thus, the length of this interaction is unlikely to be, responsible for differences in colour. Crystallographic data presented, here taken together ... | Copper-containing nitrite reductases (NiR's) have been conveniently, subdivided into blue and green NiR's which are thought to be redox, partners of azurins and pseudo-azurins, respectively. Crystal structures, of two green NiR's have recently been determined. Alcaligenes xylosoxidans, has been shown to have a blue-copper nitrite reductase (AxNiR) and two, azurins with 67% homology both of which donate electrons to it, effectively. The first crystal structure of a blue NiR (AxNiR) in its, oxidized and nitrite-bound forms, with particular emphasis to the Cu, sites, is presented. The Cu-Smet distance is the same as those in the, green NiR's. Thus, the length of this interaction is unlikely to be, responsible for differences in colour. Crystallographic data presented, here taken together with structural data of other single Cu type-1, proteins and their mutants suggest that the displacement of Cu from the, strong ligand plane is perhaps the cause for the differences in colour, observed for otherwise 'classical' blue Cu centre. Nitrite is observed, binding to the catalytic Cu in a bidentate fashion displacing the water, molecule, offering a neat rationalization for the XAFS observation that, the type-2 Cu-ligand distances increase on nitrite binding as a result of, increased coordination. These results are discussed in terms of enzyme, mechanism. | ||
==About this Structure== | ==About this Structure== | ||
1NDS is a | 1NDS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Achromobacter_xylosoxidans Achromobacter xylosoxidans] with CU and NO2 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Transferred_entry:_1.7.2.1 Transferred entry: 1.7.2.1], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.7.99.3 1.7.99.3] Structure known Active Sites: AC1, AC2, BC1, BC2, CC1 and CC2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1NDS OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: reductase]] | [[Category: reductase]] | ||
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Revision as of 14:39, 5 November 2007
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CRYSTALLOGRAPHIC STRUCTURE OF A SUBSTRATE BOUND BLUE COPPER NITRITE REDUCTASE FROM ALCALIGENES XYLOSOXIDANS
OverviewOverview
Copper-containing nitrite reductases (NiR's) have been conveniently, subdivided into blue and green NiR's which are thought to be redox, partners of azurins and pseudo-azurins, respectively. Crystal structures, of two green NiR's have recently been determined. Alcaligenes xylosoxidans, has been shown to have a blue-copper nitrite reductase (AxNiR) and two, azurins with 67% homology both of which donate electrons to it, effectively. The first crystal structure of a blue NiR (AxNiR) in its, oxidized and nitrite-bound forms, with particular emphasis to the Cu, sites, is presented. The Cu-Smet distance is the same as those in the, green NiR's. Thus, the length of this interaction is unlikely to be, responsible for differences in colour. Crystallographic data presented, here taken together with structural data of other single Cu type-1, proteins and their mutants suggest that the displacement of Cu from the, strong ligand plane is perhaps the cause for the differences in colour, observed for otherwise 'classical' blue Cu centre. Nitrite is observed, binding to the catalytic Cu in a bidentate fashion displacing the water, molecule, offering a neat rationalization for the XAFS observation that, the type-2 Cu-ligand distances increase on nitrite binding as a result of, increased coordination. These results are discussed in terms of enzyme, mechanism.
About this StructureAbout this Structure
1NDS is a Single protein structure of sequence from Achromobacter xylosoxidans with CU and NO2 as ligands. Active as Transferred entry: 1.7.2.1, with EC number 1.7.99.3 Structure known Active Sites: AC1, AC2, BC1, BC2, CC1 and CC2. Full crystallographic information is available from OCA.
ReferenceReference
Structures of a blue-copper nitrite reductase and its substrate-bound complex., Dodd FE, Hasnain SS, Abraham ZH, Eady RR, Smith BE, Acta Crystallogr D Biol Crystallogr. 1997 Jul 1;53(Pt 4):406-18. PMID:15299906
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