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[[Image:1aof.gif|left|200px]]<br />
<applet load="1aof" size="450" color="white" frame="true" align="right" spinBox="true"
caption="1aof, resolution 2.0&Aring;" />
'''CYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORM'''<br />


==Overview==
==CYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORM==
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.
<StructureSection load='1aof' size='340' side='right'caption='[[1aof]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1aof]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Paracoccus_pantotrophus Paracoccus pantotrophus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1AOF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1AOF FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DHE:HEME+D'>DHE</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=SO2:SULFUR+DIOXIDE'>SO2</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1aof FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1aof OCA], [https://pdbe.org/1aof PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1aof RCSB], [https://www.ebi.ac.uk/pdbsum/1aof PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1aof ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NIRS_PARPN NIRS_PARPN]
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ao/1aof_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1aof ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== 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.


==About this Structure==
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<ref>PMID:9311786</ref>
1AOF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Paracoccus_pantotrophus Paracoccus pantotrophus] with HEM, DHE and SO2 as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Sites: C1A, C1B, D1A and D1B. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1AOF OCA].


==Reference==
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9311786 9311786]
</div>
<div class="pdbe-citations 1aof" style="background-color:#fffaf0;"></div>
 
==See Also==
*[[Cytochrome c nitrite reductase|Cytochrome c nitrite reductase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Paracoccus pantotrophus]]
[[Category: Paracoccus pantotrophus]]
[[Category: Single protein]]
[[Category: Fulop V]]
[[Category: Fulop, V.]]
[[Category: Williams PA]]
[[Category: Williams, P.A.]]
[[Category: DHE]]
[[Category: HEM]]
[[Category: SO2]]
[[Category: enzyme]]
[[Category: nitrate assimilation]]
[[Category: nitrite reductase]]
[[Category: oxidoreductase]]
 
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov  5 15:49:58 2007''

Latest revision as of 09:22, 30 October 2024

CYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORMCYTOCHROME CD1 NITRITE REDUCTASE, REDUCED FORM

Structural highlights

1aof 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.
Method:X-ray diffraction, Resolution 2Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

NIRS_PARPN

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[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Williams PA, Fulop V, Garman EF, Saunders NF, Ferguson SJ, Hajdu J. Haem-ligand switching during catalysis in crystals of a nitrogen-cycle enzyme. Nature. 1997 Sep 25;389(6649):406-12. PMID:9311786 doi:10.1038/38775

1aof, resolution 2.00Å

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