6cdk | pdb_00006cdk

Characterization of the P1+ intermediate state of nitrogenase P-cluster

spinqualitylabelsall models 6cdk, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6cdk is a 4 chain structure with sequence from Azotobacter vinelandii. This structure supersedes the now removed PDB entry 5ijy. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: CLF, FE, HCA, ICS 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 Nitrogenase is the enzyme that reduces atmospheric dinitrogen (N2) to ammonia (NH3) in biological systems. It catalyzes a series of single-electron transfers from the donor iron protein (Fe protein) to the molybdenum-iron protein (MoFe protein) that contains the iron-molybdenum cofactor (FeMo-co) sites where N2 is reduced to NH3 The [8Fe-7S] P-cluster in the MoFe protein functions in nitrogenase catalysis as an intermediate electron carrier between the external electron donor, the Fe protein, and the FeMo-co sites of the MoFe protein. Previous work has revealed that the P-cluster undergoes redox dependent structural changes and that the transition from the all-ferrous resting (P(N)) state to the two electron oxidized P(2+) state is accompanied by protein serince hydroxyl and backbone amide ligation to Fe. In this work, the MoFe protein was poised at defined potentials with redox mediators in an electrochemical cell, and the three distinct structural states of the P-cluster (P(2+), P(1+), and P(N)) were characterized by X-ray crystallography and confirmed by computational analysis. These analyses revealed that the three oxidation states differ in coordination implicating that the P(1+) state retains the serine hydroxyl coordination but lacks the backbone amide coordination observed in the P(2+) states. These results provide a complete picture of the redox-dependent ligand rearrangements of the three P-cluster redox states. Structural characterization of the P(1+) intermediate state of the P-cluster of nitrogenase.,Keable SM, Zadvornyy OA, Johnson LE, Ginovska B, Rasmussen AJ, Danyal K, Eilers BJ, Prussia GA, LeVan AX, Raugei S, Seefeldt LC, Peters JW J Biol Chem. 2018 May 2. pii: RA118.002435. doi: 10.1074/jbc.RA118.002435. PMID:29720402 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nitrogenase 3D structures

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