1h9x: Difference between revisions

Revision as of 18:37, 2 May 2008

CYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORM

OverviewOverview

Cytochrome cd(1) nitrite reductase is a bifunctional enzyme, which can catalyze the 1-electron reduction of nitrite to nitric oxide and the 4-electron reduction of dioxygen to water. Here we describe the structure of reduced nitrite reductase, crystallized under anaerobic conditions. The structure reveals substantial domain rearrangements with the c domain rotated by 60 degrees and shifted by approximately 20 A compared with previously known structures from crystals grown under oxidizing conditions. This alternative conformation gives rise to different electron transfer routes between the c and d(1) domains and points to the involvement of elements of very large structural changes in the function in this enzyme. In the present structure, the c heme has a His-69/Met-106 ligation, and this ligation does not change upon oxidation in the crystal. The d(1) heme is penta-coordinated, and the d(1) iron is displaced from the heme plane by 0.5 A toward the proximal ligand, His-200. After oxidation, the iron moves into the d(1) heme plane. A surprising finding is that although reduced nitrite reductase can be readily oxidized by dioxygen in the new crystal, it cannot turnover with its other substrate, nitrite. The results suggest that the rearrangement of the domains affects catalysis and substrate selectivity.

About this StructureAbout this Structure

1H9X is a Single protein structure of sequence from Paracoccus pantotrophus. Full crystallographic information is available from OCA.

ReferenceReference

The Structure of an alternative form of Paracoccus pantotrophus cytochrome cd(1) nitrite reductase., Sjogren T, Hajdu J, J Biol Chem. 2001 Aug 3;276(31):29450-5. Epub 2001 May 23. PMID:11373294 Page seeded by OCA on Fri May 2 18:37:08 2008

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OCA

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 [[Image:1h9x.gif|left|200px]]
- {{Structure
+<!--
-|PDB= 1h9x |SIZE=350|CAPTION= <scene name='initialview01'>1h9x</scene>, resolution 2.1&Aring;
+The line below this paragraph, containing "STRUCTURE_1h9x", creates the "Structure Box" on the page.
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+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=DHE:HEME+D'>DHE</scene>, <scene name='pdbligand=HEC:HEME+C'>HEC</scene>, <scene name='pdbligand=NHE:2-[N-CYCLOHEXYLAMINO]ETHANE+SULFONIC+ACID'>NHE</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY=
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1h9x|  PDB=1h9x  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1h9x FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1h9x OCA], [http://www.ebi.ac.uk/pdbsum/1h9x PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1h9x RCSB]</span>
-}}
 '''CYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORM'''
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 [[Category: Hajdu, J.]]
 [[Category: Sjogren, T.]]
-[[Category: enzyme]]
+[[Category: Enzyme]]
-[[Category: nitrite reductase]]
+[[Category: Nitrite reductase]]
-[[Category: oxidoreductase]]
+[[Category: Oxidoreductase]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 18:37:08 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 21:00:49 2008''