1m1y

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CFM:FE-MO-S+CLUSTER'>CFM</scene>, <scene name='pdbligand=CLF:FE(8)-S(7)+CLUSTER'>CLF</scene>, <scene name='pdbligand=HCA:3-HYDROXY-3-CARBOXY-ADIPIC+ACID'>HCA</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Nitrogenase Nitrogenase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.18.6.1 1.18.6.1] </span></td></tr>

[[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. [[https://www.uniprot.org/uniprot/NIFH1_AZOVI NIFH1_AZOVI]] The key enzymatic reactions in nitrogen fixation are catalyzed by the nitrogenase complex, which has 2 components: the iron protein (component 2) and a component 1 which is either a molybdenum-iron protein, a vanadium-iron, or an iron-iron protein.[HAMAP-Rule:MF_00533] [[https://www.uniprot.org/uniprot/NIFK_AZOVI NIFK_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 ==

The transient formation of a complex between the component Fe- and MoFe-proteins of nitrogenase represents a central event in the substrate reduction mechanism of this enzyme. Previously, we have isolated an N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide (EDC) cross-linked complex of these proteins stabilized by a covalent isopeptide linkage between Glu 112 and Lys beta400 of the Fe-protein and MoFe-protein, respectively [Willing, A., et al. (1989) J. Biol. Chem. 264, 8499-8503; Willing, A., and Howard, J. B. (1990) J. Biol. Chem. 265, 6596-6599]. We report here the biochemical and structural characterization of the cross-linked complex to assess the mechanistic relevance of this species. Glycinamide inhibits the cross-linking reaction, and is found to be specifically incorporated into Glu 112 of the Fe-protein, without detectable modification of either of the neighboring residues (Glu 110 and Glu 111). This modified protein is still competent for substrate reduction, demonstrating that formation of the cross-linked complex is responsible for the enzymatic inactivation, and not the EDC reaction or the modification of the Fe-protein. Crystallographic analysis of the EDC-cross-linked complex at 3.2 A resolution confirms the site of the isopeptide linkage. The nature of the protein surfaces around the cross-linking site suggests there is a strong electrostatic component to the formation of the complex, although the interface area between the component proteins is small. The binding footprints between proteins in the cross-linked complex are adjacent, but with little overlap, to those observed in the complex of the nitrogenase proteins stabilized by ADP-AlF(4)(-). The results of these studies suggest that EDC cross-linking traps a nucleotide-independent precomplex of the nitrogenase proteins driven by complementary electrostatic interactions that subsequently rearranges in a nucleotide-dependent fashion to the electron transfer competent state observed in the ADP-AlF(4)(-) structure.

Biochemical and structural characterization of the cross-linked complex of nitrogenase: comparison to the ADP-AlF4(-)-stabilized structure.,Schmid B, Einsle O, Chiu HJ, Willing A, Yoshida M, Howard JB, Rees DC Biochemistry. 2002 Dec 31;41(52):15557-65. PMID:12501184<ref>PMID:12501184</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Chiu, H J]]

[[Category: Einsle, O]]

[[Category: Howard, J B]]

[[Category: Rees, D C]]

[[Category: Schmid, B]]

[[Category: Willing, A]]

[[Category: Yoshida, M]]

[[Category: Protein interaction]]