MoFe nitrogenase protein

Fig. 6. View of the nitrogenase MoFe protein P-cluster pair where ( ) represents Fe, (O) S, and (Q) C as modeled (153). The side chain of one of the...

Fig. 7. View of the FeMo-cofactor prosthetic group of the nitrogenase MoFe protein with some of the surrounding amino acid residues where ( ) represents the molybdenum coordinated to a-His-442 and homocitrate (at the top), ( ) represents the iron, interspersed with the sulfur (O) and carbon...

Schmid B, Ribbe MW, Einsle O, et al. Structure of a Cofactor-Deficient Nitrogenase MoFe Protein. Science 2002 296 352-6. 

Einsle O, Tezcan FA, Andrade SL, et al. Nitrogenase MoFe-protein at 1.16 A resolution A central ligand in the FeMo-cofactor. Science 2002 297 1696-700. 

Nitrogenase MoFe protein NADH dehydrogenase Respiratory nitrate reductase Assimilatory nitrate reductase Sulfite oxidase Aldehyde oxidase Xanthine oxidase Xanthine dehydrogenase... 

DeRose, V.J. C.-H., Kim, W.E., Newton, D. R.D., and Hoffman B. M. (1995) Electron Spin Echo Modulation Spectroscopic Analysis of Altered Nitrogenase MoFe Proteins of Azotobacter vinelandii, Biochemistry 34, 2809-2814... 

Peters, J. W.K. Fisher, W.E. Newton, and D.R.Dean, "Involvement of the P Cluster in Intramolecular Electron Transfer within the Nitrogenase MoFe Protein", J. Biol. Chem. 270, 27007-27013 (1995). 

Figure 12 35 GHz Fe and H CW ENDOR spectra of the hi-CO form of nitrogenase MoFe protein with varying types of Fe-enrichment. The H signals are included as intensity standards since the natural ahundance samples contain ohservahle amounts of Fe. The spectra were recorded at gobs = 2.06 (gj ). Cartoons on the left indicate the specific sample, wherein the FeMo-cofactor is indicated hy the diamond shape (in green), and the P-cluster is indicated by the two cubes (in red). These shapes roughly represent the clusters actual strucmres. Fe-enriched sites are indicated as colored blocks. The abbreviations used are as follows M(56)P(56) is natural abundance FeMo-cofactor and P-cluster M(56)P(57) is natural abundance FeMo-cofactor and enriched P-cluster M(57)P(56) is enriched FeMo-cofactor and natural abundance P-cluster M(57)P(57) is enriched FeMo-cofactor and P-cluster (i.e., globally enriched MoFe protein). (Adapted from Figure 1 in Christie, Lee, Cameron, Hales, Orme-Johnson and Hoffman. Reprinted with permission, 1996 American Chemical Society)...

The MoFe cofactor of the nitrogenase MoFe-protein component... 

Mo K-edge EXAFS spectrum (left panel) and EXAFS Fourier transform (right panel) of Klebsiella pneumoniae nitrogenase MoFe protein. The solid line is the processed experimental spectrum and the dashed line a calculated one. ... 

Bolin JT, Campobasso N, Muchmoee SW, Morgan TV and Moetenson LE (1993) The structure and environment of the metal clusters in the nitrogenase MoFe protein from Clostridium pasteurianum. In Stiefel El, Coucouvanis D and Newton WE, eds. Molybdenum enzymes, cofactors and model systems, pp. 186-195. American Chemical Society, Washington, D. C. 

A famous example is the structure of Nitrogenase MoFe-Protein, a protein that contains a Fe7MoS9 cluster. The inside of this cluster is about 4 A wide with six iron atoms closest to the centre, and older crystal stmctures had been determined at resolutions of about 2 A. Termination of the Fourier summation at that resolution creates an artefactual miiumum in the electron density of about —0.2 electrons about 2 A away from each iron atom. These spurious minima from all heavy atoms in the... 

Information about the bonding of hydrazine (see above) was obtained from experiments using the a-195-Gln-substituted nitrogenase MoFe protein, in which the proton shuttle to the active site is impaired, and the substrate methyldiazene. Freeze-quenching under turnover conditions trapped a 5 = 1/2 state that was characterized by EPR and ENDOR spectroscopies. Furthermore, a diazene-bound intermediate was obtained from the doubly substituted a-70Ala/a-195Gln MoFe protein and investigated spectroscopically. ... 

Fig. 5. The structure of the P cluster prosthetic group of A vinelandii nitrogenase MoFe protein in its dye-oxidized (left) and normal dithionite-reduced (right) states. The coordinating amino acid residues (a-Cys-62, a-Cys-88, a-Cys-154, 8-Cys-70, )3-Cys-95, j8-Cys-153, and /S-Ser-188) are provided by both the a- and 8-subunits. The Fe atoms are the larger darker spheres and the S atoms are the medium-colored and medium-size spheres (38 PDB code 3MIN and 2MIN). See the text for how the two structures are proposed to interconvert during catalysis.

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