View source for 1nir


==OXYDIZED NITRITE REDUCTASE FROM PSEUDOMONAS AERUGINOSA==
<StructureSection load='1nir' size='340' side='right'caption='[[1nir]], [[Resolution|resolution]] 2.15&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1nir]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1NIR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1NIR 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]] 2.15&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=HEC:HEME+C'>HEC</scene>, <scene name='pdbligand=OH:HYDROXIDE+ION'>OH</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=1nir FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1nir OCA], [https://pdbe.org/1nir PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1nir RCSB], [https://www.ebi.ac.uk/pdbsum/1nir PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1nir ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/NIRS_PSEAE NIRS_PSEAE] 
== 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/ni/1nir_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=1nir ConSurf].
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== Publication Abstract from PubMed ==
BACKGROUND: Nitrite reductase from Pseudomonas aeruginosa (NiR-Pa) is a dimer consisting of two identical 60 kDa subunits, each of which contains one c and one d1 heme group. This enzyme, a soluble component of the electron-transfer chain that uses nitrate as a source of energy, can be induced by the addition of nitrate to the bacterial growth medium. NiR-Pa catalyzes the reduction of nitrite (NO2-) to nitric oxide (NO); in vitro, both cytochrome c551 and azurin are efficient electron donors in this reaction. NiR is a key denitrification enzyme, which controls the rate of the production of toxic nitric oxide (NO) and ultimately regulates the release of NO into the atmosphere. RESULTS: The structure of the orthorhombic form (P2(1)2(1)2) of oxidized NiR-Pa was solved at 2.15 A resolution, using molecular replacement with the coordinates of the NiR from Thiosphaera pantotropha (NiR-Tp) as the starting model. Although the d1-heme domains are almost identical in both enzyme structures, the c domain of NiR-Pa is more like the classical class I cytochrome-c fold because it has His51 and Met88 as heme ligands, instead of His17 and His69 present in NiR-Tp. In addition, the methionine-bearing loop, which was displaced by His17 of the NiR-Tp N-terminal segment, is back to normal in our structure. The N-terminal residues (5/6-30) of NiR-Pa and NiR-Tp have little sequence identity. In Nir-Pa, this N-terminal segment of one monomer crosses the dimer interface and wraps itself around the other monomer. Tyr10 of this segment is hydrogen bonded to an hydroxide ion--the sixth ligand of the d1-heme Fe, whereas the equivalent residue in NiR-Tp, Tyr25, is directly bound to the Fe. CONCLUSIONS: Two ligands of hemes c and d1 differ between the two known NiR structures, which accounts for the fact that they have quite different spectroscopic and kinetic features. The unexpected domain-crossing by the N-terminal segment of NiR-Pa is comparable to that of 'domain swapping' or 'arm exchange' previously observed in other systems and may explain the observed cooperativity between monomers of dimeric NiR-Pa. In spite of having similar sequence and fold, the different kinetic behaviour and the spectral features of NiR-Pa and NiR-Tp are tuned by the N-terminal stretch of residues. A further example of this may come from another NiR, from Pseudomonas stutzeri, which has an N terminus very different from that of the two above mentioned NiRs.

N-terminal arm exchange is observed in the 2.15 A crystal structure of oxidized nitrite reductase from Pseudomonas aeruginosa.,Nurizzo D, Silvestrini MC, Mathieu M, Cutruzzola F, Bourgeois D, Fulop V, Hajdu J, Brunori M, Tegoni M, Cambillau C Structure. 1997 Sep 15;5(9):1157-71. PMID:9331415<ref>PMID:9331415</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Cytochrome c nitrite reductase|Cytochrome c nitrite reductase]]
== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Pseudomonas aeruginosa]]
[[Category: Cambillau C]]
[[Category: Nurizzo D]]
[[Category: Tegoni M]]