9cjf

CryoEM structure of alkaline-inactivated nitrogenase MoFe-protein in complex with NafT

spinqualitylabelsall models 9cjf, resolution 2.33Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9cjf is a 5 chain structure with sequence from Azotobacter vinelandii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.33Å Ligands: 1N7, FE Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NIFD_AZOVI This molybdenum-iron protein is part of the nitrogenase complex that catalyzes the key enzymatic reactions in nitrogen fixation. Publication Abstract from PubMed Biological nitrogen fixation, performed by the enzyme nitrogenase, supplies nearly 50% of the bioavailable nitrogen pool on Earth, yet the structural nature of the enzyme intermediates involved in this cycle remains ambiguous. Here we present four high resolution cryoEM structures of the nitrogenase MoFe-protein, sampled along a time course of alkaline reaction mixtures under an acetylene atmosphere. This series of structures reveals a sequence of salient changes including perturbations to the inorganic framework of the FeMo-cofactor; depletion of the homocitrate moiety; diminished density around the S2B belt sulfur of the FeMo-cofactor; rearrangements of cluster-adjacent side chains; and the asymmetric displacement of the FeMo-cofactor. We further demonstrate that the nitrogenase associated factor T protein can recognize and bind an alkaline inactivated MoFe-protein in vitro. These time-resolved structures provide experimental support for the displacement of S2B and distortions of the FeMo-cofactor at the E(0)-E(3) intermediates of the substrate reduction mechanism, prior to nitrogen binding, highlighting cluster rearrangements potentially relevant to nitrogen fixation by biological and synthetic clusters. Structural evolution of nitrogenase states under alkaline turnover.,Warmack RA, Rees DC Nat Commun. 2024 Dec 2;15(1):10472. doi: 10.1038/s41467-024-54713-0. PMID:39622820 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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