1aom

SUBSTRATE AND PRODUCT BOUND TO CYTOCHROME CD1 NITRITE REDUCTASE

spinqualitylabelsall models 1aom, resolution 1.80Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1aom is a 2 chain structure with sequence from Paracoccus pantotrophus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 2NO, DHE, HEM, NO Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 Cytochrome cd1 nitrite reductase catalyses the conversion of nitrite to nitric oxide in the nitrogen cycle. The crystal structure of the oxidized enzyme shows that the d1 haem iron of the active site is ligated by His/Tyr side chains, and the c haem iron is ligated by a His/His ligand pair. Here we show that both haems undergo re-ligation during catalysis. Upon reduction, the tyrosine ligand of the d1 haem is released to allow substrate binding. Concomitantly, a refolding of the cytochrome c domain takes place, resulting in an unexpected change of the c haem iron coordination from His 17/His 69 to Met106/His69. This step is similar to the last steps in the folding of cytochrome c. The changes must affect the redox potential of the haems, and suggest a mechanism by which internal electron transfer is regulated. Structures of reaction intermediates show how nitric oxide is formed and expelled from the active-site iron, as well as how both haems return to their starting coordination. These results show how redox energy can be switched into conformational energy within a haem protein. Haem-ligand switching during catalysis in crystals of a nitrogen-cycle enzyme.,Williams PA, Fulop V, Garman EF, Saunders NF, Ferguson SJ, Hajdu J Nature. 1997 Sep 25;389(6649):406-12. PMID:9311786 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nitrite reductase

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