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==Characterization of the P1+ intermediate state of nitrogenase P-cluster==
<StructureSection load='6cdk' size='340' side='right'caption='[[6cdk]], [[Resolution|resolution]] 2.10&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6cdk]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Azotobacter_vinelandii Azotobacter vinelandii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6CDK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6CDK 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]] 2.1&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FE:FE+(III)+ION'>FE</scene>, <scene name='pdbligand=HCA:3-HYDROXY-3-CARBOXY-ADIPIC+ACID'>HCA</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=6cdk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6cdk OCA], [https://pdbe.org/6cdk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6cdk RCSB], [https://www.ebi.ac.uk/pdbsum/6cdk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6cdk ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NIFD_AZOVI NIFD_AZOVI] This molybdenum-iron protein is part of the nitrogenase complex that catalyzes the key enzymatic reactions in nitrogen fixation.
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== Publication Abstract from PubMed ==
Nitrogenase is the enzyme that reduces atmospheric dinitrogen (N2) to ammonia (NH3) in biological systems. It catalyzes a series of single-electron transfers from the donor iron protein (Fe protein) to the molybdenum-iron protein (MoFe protein) that contains the iron-molybdenum cofactor (FeMo-co) sites where N2 is reduced to NH3 The [8Fe-7S] P-cluster in the MoFe protein functions in nitrogenase catalysis as an intermediate electron carrier between the external electron donor, the Fe protein, and the FeMo-co sites of the MoFe protein. Previous work has revealed that the P-cluster undergoes redox dependent structural changes and that the transition from the all-ferrous resting (P(N)) state to the two electron oxidized P(2+) state is accompanied by protein serince hydroxyl and backbone amide ligation to Fe. In this work, the MoFe protein was poised at defined potentials with redox mediators in an electrochemical cell, and the three distinct structural states of the P-cluster (P(2+), P(1+), and P(N)) were characterized by X-ray crystallography and confirmed by computational analysis. These analyses revealed that the three oxidation states differ in coordination implicating that the P(1+) state retains the serine hydroxyl coordination but lacks the backbone amide coordination observed in the P(2+) states. These results provide a complete picture of the redox-dependent ligand rearrangements of the three P-cluster redox states.

Structural characterization of the P(1+) intermediate state of the P-cluster of nitrogenase.,Keable SM, Zadvornyy OA, Johnson LE, Ginovska B, Rasmussen AJ, Danyal K, Eilers BJ, Prussia GA, LeVan AX, Raugei S, Seefeldt LC, Peters JW J Biol Chem. 2018 May 2. pii: RA118.002435. doi: 10.1074/jbc.RA118.002435. PMID:29720402<ref>PMID:29720402</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6cdk" style="background-color:#fffaf0;"></div>

==See Also==
*[[Nitrogenase 3D structures|Nitrogenase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Azotobacter vinelandii]]
[[Category: Large Structures]]
[[Category: Danyal K]]
[[Category: Eilers BJ]]
[[Category: Keable SM]]
[[Category: LeVan AX]]
[[Category: Peters JW]]
[[Category: Prussia GA]]
[[Category: Rasmussen AJ]]
[[Category: Seefeldt LC]]
[[Category: Zadvornyy OA]]