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| == Function == | | == Function == |
| [https://www.uniprot.org/uniprot/A9H5W5_GLUDA A9H5W5_GLUDA] | | [https://www.uniprot.org/uniprot/A9H5W5_GLUDA A9H5W5_GLUDA] |
| <div style="background-color:#fffaf0;">
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| == Publication Abstract from PubMed ==
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| The P-cluster is a unique iron-sulfur center that likely functions as a dynamic electron (e(-)) relay site between the Fe-protein and the catalytic FeMo-cofactor in nitrogenase. The P-cluster has been shown to undergo large conformational changes upon 2-e(-) oxidation which entail the coordination of two of the Fe centers to a Ser side chain and a backbone amide N, respectively. Yet, how and if this 2-e(-) oxidized state (P(OX)) is involved in catalysis by nitrogenase is not well established. Here, we present the crystal structures of reduced and oxidized MoFe-protein (MoFeP) from Gluconacetobacter diazotrophicus (Gd), which natively possesses an Ala residue in the position of the Ser ligand to the P-cluster. While reduced Gd-MoFeP is structurally identical to previously characterized counterparts around the FeMo-cofactor, oxidized Gd-MoFeP features an unusual Tyr coordination to its P-cluster along with ligation by a backbone amide nitrogen. EPR analysis of the oxidized Gd-MoFeP P-cluster confirmed that it is a 2-e(-) oxidized, integer-spin species. Importantly, we have found that the sequence positions corresponding to the Ser and Tyr ligands are almost completely covariant among Group I nitrogenases. These findings strongly support the possibility that the P(OX) state is functionally relevant in nitrogenase catalysis and that a hard, O-based anionic ligand serves to stabilize this state in a switchable fashion.
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| Tyrosine-Coordinated P-Cluster in G. diazotrophicus Nitrogenase: Evidence for the Importance of O-Based Ligands in Conformationally Gated Electron Transfer.,Owens CP, Katz FE, Carter CH, Oswald VF, Tezcan FA J Am Chem Soc. 2016 Aug 17;138(32):10124-7. doi: 10.1021/jacs.6b06783. Epub 2016 , Aug 8. PMID:27487256<ref>PMID:27487256</ref>
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| From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| </div>
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| <div class="pdbe-citations 5koj" style="background-color:#fffaf0;"></div>
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| ==See Also== | | ==See Also== |
| *[[Nitrogenase 3D structures|Nitrogenase 3D structures]] | | *[[Nitrogenase 3D structures|Nitrogenase 3D structures]] |
| == References ==
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| <references/>
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| __TOC__ | | __TOC__ |
| </StructureSection> | | </StructureSection> |
