Molybdenum nitrogenase biosynthesis

Figure 12 Assembly of the molybdenum nitrogenase. Pathways of FeMo cofactor biosynthesis, Fe protein maturation, and MoFe protein assembly are indicated in dotted, dashed, and solid arrows, respectively. The nif gene products that are also required for the vanadium and iron-only nitrogenase systems are indicated by ...

The assembly of the molybdenum nitrogenase Fe protein involves the nifH gene and at least the nifS, nifU, and niJM gene prodncts that are implicated in the [4Fe 4S] cluster assembly, while the assembly of MoFe protein requires at least 15 nif gene products and involves the biosynthesis of FeMo cofactor and FeMo cofactor deficient MoFe protein in separate pathways and the insertion of FeMo cofactor into the MoFe protein. 

As well as donating electrons to the MoFe protein, the Fe protein has at least two and possibly three other functions (see Section IV,C) It is involved in the biosynthesis of the iron molybdenum cofactor, FeMoco it is required for insertion of the FeMoco into the MoFe protein polypeptides and it has been implicated in the regulation of the biosynthesis of the alternative nitrogenases. 

K), Fe-S cluster assembly (nIfM) and the biosynthesis of the iron molybdenum cofactor, FeMo-co (nifN, B, E, Q, V, H)(5a). It is the last two functions, involving the placement of unusual transition metal sulfide clusters into the nitrogenase proteins, that cause nitrogenase and its components to be appropriately included in this symposium. 

Cobalt B Enzymes Coenzymes Cytochrome Oxidase Iron Heme Proteins Electron Transport Iron Proteins with Dinuclear Active Sites Iron Proteins with Mononuclear Active Sites Iron-Sulfur Models of Protein Active Sites Metallocenter Biosynthesis Assembly. Metalloregulation Molybdenum MPT-containing Enzymes Nickel Enzymes Cofactors Nitrogenase Catalysis Assembly Photosynthesis Tungsten Proteins Vanadium in Biology Zinc DNA-binding Proteins. 

R. Allen, T. Paustian, J. Roll, R. Chatterjee, M. Madden and J. Allen, Biosynthesis of the iron-molybdenum cofactor of nitrogenase, in Molybdenum Enzymes, Cofactors and Model Systems , eds. E. 1. Stiefel, D. Coucouvanis, and W. E. Newton, American Chemical Society, Washington, DC, 1993, p. 196. 

Rubio, L. M., Ludden, P. W. (2008). Biosynthesis of the iron-molybdenum cofactor of nitrogenase. Annual Review of Microbiology, 62, 93-111. 

In biological systems Mo is present as the Fe/Mo cofactor of the nitrogenase enzymes (2) and of the multitude of oxidoreductases (3). In the latter the common molybdopterin cofactor (4), in addition to a dithiolene functionalized pyranopterin (5) ligand (Fig. 1), contains terminal oxo ligands and in the case of xanthine oxidase both oxo and thio ligands. Some aspects of molybdenum sulfur chemistry discussed in this work may be relevant to the biosynthesis of the molybdopterin cofactor and the function of xanthine oxidase (6). 

Biosynthesis of the Nitrogenase Iron-Molybdenum-Cofactor from Azotobacter vinelandii... 

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