View source for 2nya


==Crystal structure of the periplasmic nitrate reductase (NAP) from Escherichia coli==
<StructureSection load='2nya' size='340' side='right'caption='[[2nya]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2nya]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NYA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2NYA 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=6MO:MOLYBDENUM(VI)+ION'>6MO</scene>, <scene name='pdbligand=MGD:2-AMINO-5,6-DIMERCAPTO-7-METHYL-3,7,8A,9-TETRAHYDRO-8-OXA-1,3,9,10-TETRAAZA-ANTHRACEN-4-ONE+GUANOSINE+DINUCLEOTIDE'>MGD</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</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=2nya FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2nya OCA], [https://pdbe.org/2nya PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2nya RCSB], [https://www.ebi.ac.uk/pdbsum/2nya PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2nya ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NAPA_ECOLI NAPA_ECOLI] Catalytic subunit of the periplasmic nitrate reductase (NAP). Only expressed at high levels during aerobic growth. NapAB complex receives electrons from the membrane-anchored tetraheme protein NapC, thus allowing electron flow between membrane and periplasm. Essential function for nitrate assimilation and may have a role in anaerobic metabolism (By similarity).[HAMAP-Rule:MF_01630]
== 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/ny/2nya_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.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=2nya ConSurf].
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== Publication Abstract from PubMed ==
The Escherichia coli NapA (periplasmic nitrate reductase) contains a [4Fe-4S] cluster and a Mo-bis-molybdopterin guanine dinucleotide cofactor. The NapA holoenzyme associates with a di-heme c-type cytochrome redox partner (NapB). These proteins have been purified and studied by spectropotentiometry, and the structure of NapA has been determined. In contrast to the well characterized heterodimeric NapAB systems ofalpha-proteobacteria, such as Rhodobacter sphaeroides and Paracoccus pantotrophus, the gamma-proteobacterial E. coli NapA and NapB proteins purify independently and not as a tight heterodimeric complex. This relatively weak interaction is reflected in dissociation constants of 15 and 32 mum determined for oxidized and reduced NapAB complexes, respectively. The surface electrostatic potential of E. coli NapA in the apparent NapB binding region is markedly less polar and anionic than that of the alpha-proteobacterial NapA, which may underlie the weaker binding of NapB. The molybdenum ion coordination sphere of E. coli NapA includes two molybdopterin guanine dinucleotide dithiolenes, a protein-derived cysteinyl ligand and an oxygen atom. The Mo-O bond length is 2.6 A, which is indicative of a water ligand. The potential range over which the Mo(6+) state is reduced to the Mo(5+) state in either NapA (between +100 and -100 mV) or the NapAB complex (-150 to -350 mV) is much lower than that reported for R. sphaeroides NapA (midpoint potential Mo(6+/5+) &gt; +350 mV), and the form of the Mo(5+) EPR signal is quite distinct. In E. coli NapA or NapAB, the Mo(5+) state could not be further reduced to Mo(4+). We then propose a catalytic cycle for E. coli NapA in which nitrate binds to the Mo(5+) ion and where a stable des-oxo Mo(6+) species may participate.

Spectropotentiometric and structural analysis of the periplasmic nitrate reductase from Escherichia coli.,Jepson BJ, Mohan S, Clarke TA, Gates AJ, Cole JA, Butler CS, Butt JN, Hemmings AM, Richardson DJ J Biol Chem. 2007 Mar 2;282(9):6425-37. Epub 2006 Nov 27. PMID:17130127<ref>PMID:17130127</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Nitrate reductase|Nitrate reductase]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Hemmings AM]]
[[Category: Jepson BJN]]
[[Category: Richardson DJ]]