View source for 6o7o


==Nitrogenase MoFeP mutant F99Y/S188A from Azotobacter vinelandii in the dithionite reduced state after redox cycling==
<StructureSection load='6o7o' size='340' side='right'caption='[[6o7o]], [[Resolution|resolution]] 1.89&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6o7o]] 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=6O7O OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6O7O 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]] 1.89&#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=6o7o FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6o7o OCA], [https://pdbe.org/6o7o PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6o7o RCSB], [https://www.ebi.ac.uk/pdbsum/6o7o PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6o7o 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.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Molybdenum nitrogenase catalyzes the reduction of dinitrogen into ammonia, which requires the coordinated transfer of eight electrons to the active site cofactor (FeMoco) through the intermediacy of an [8Fe-7S] cluster (P-cluster), both housed in the molybdenum-iron protein (MoFeP). Previous studies on MoFeP from two different organisms, Azotobacter vinelandii ( Av) and Gluconacetobacter diazotrophicus ( Gd), have established that the P-cluster is conformationally flexible and can undergo substantial structural changes upon two-electron oxidation to the P(OX) state, whereby a backbone amidate and an oxygenic residue (Ser or Tyr) ligate to two of the cluster's Fe centers. This redox-dependent change in coordination has been implicated in the conformationally gated electron transfer in nitrogenase. Here, we have investigated the role of the oxygenic ligand in Av MoFeP, which natively contains a Ser ligand (betaSer188) to the P-cluster. Three variants were generated in which (1) the oxygenic ligand was eliminated (betaSer188Ala), (2) the P-cluster environment was converted to the one in Gd MoFeP (betaPhe99Tyr/betaSer188Ala), and (3) two oxygenic ligands were simultaneously included (betaPhe99Tyr). Our studies have revealed that the P-cluster can become compositionally labile upon oxidation and reversibly lose one or two Fe centers in the absence of the oxygenic ligand, while still retaining wild-type-like dinitrogen reduction activity. Our findings also suggest that Av and Gd MoFePs evolved with specific preferences for Ser and Tyr ligands, respectively, and that the structural control of these ligands must extend beyond the primary and secondary coordination spheres of the P-cluster. The P-cluster adds to the increasing number of examples of inherently labile Fe-S clusters whose compositional instability may be an obligatory feature to enable redox-linked conformational changes to facilitate multielectron redox reactions.

Redox-Dependent Metastability of the Nitrogenase P-Cluster.,Rutledge HL, Rittle J, Williamson LM, Xu WA, Gagnon DM, Tezcan FA J Am Chem Soc. 2019 Jun 13. doi: 10.1021/jacs.9b04555. PMID:31146522<ref>PMID:31146522</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6o7o" style="background-color:#fffaf0;"></div>

==See Also==
*[[Nitrogenase 3D structures|Nitrogenase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Azotobacter vinelandii]]
[[Category: Large Structures]]
[[Category: Rutledge HL]]
[[Category: Tezcan FA]]