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Activated Nitrogenase MoFe-protein from Azotobacter vinelandiiActivated Nitrogenase MoFe-protein from Azotobacter vinelandii
Structural highlights
FunctionNIFD_AZOVI This molybdenum-iron protein is part of the nitrogenase complex that catalyzes the key enzymatic reactions in nitrogen fixation. Publication Abstract from PubMedThe enzyme nitrogenase uses a suite of complex metallocofactors to reduce dinitrogen (N2) to ammonia. Mechanistic details of this reaction remain sparse. We report a 1.83-angstrom crystal structure of the nitrogenase molybdenum-iron (MoFe) protein captured under physiological N2 turnover conditions. This structure reveals asymmetric displacements of the cofactor belt sulfurs (S2B or S3A and S5A) with distinct dinitrogen species in the two alphabeta dimers of the protein. The sulfur-displaced sites are distinct in the ability of protein ligands to donate protons to the bound dinitrogen species, as well as the elongation of either the Mo-O5 (carboxyl) or Mo-O7 (hydroxyl) distance that switches the Mo-homocitrate ligation from bidentate to monodentate. These results highlight the dynamic nature of the cofactor during catalysis and provide evidence for participation of all belt-sulfur sites in this process. Structural evidence for a dynamic metallocofactor during N2 reduction by Mo-nitrogenase.,Kang W, Lee CC, Jasniewski AJ, Ribbe MW, Hu Y Science. 2020 Jun 19;368(6497):1381-1385. doi: 10.1126/science.aaz6748. PMID:32554596[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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