Vanadium nitrogenases activities

NifM is required for maturation of VnfH, and NifS and U seem to be important for provision of sulfide and probably iron for the biosynthesis of the vanadium nitrogenase. The apo VFe protein has been isolated from an A. vinelandii strain deleted for nifKD and nifB (169). It was an hexamer that could be activated in vitro by the addi-... 

SCHEME 10.2 The cofactor for nitrogenase activity, an iron-sulfur-vanadium cluster. 

Lie, S., Pulakat, L., and Gavini, N. (2000) Activation of vanadium nitrogenase expression in DJ54 revertant in the presence of molybdenum, FEBS Lett 482, 149-153. 

Vanadium nitrogenase is produced by certain bacteria grown in molybdenum-deficient environments. It is effective in the reduction of N2 and other nitrogenase substrates, although with less activity than the Mo—Nase. The enzyme resembles the Mo analogue (see Sections 17-E-10 and 18-C-13) in the construction and structure of the prosthetic groups, as well as in its functions.101 It consists of a FeV protein, FeVco, and an iron protein (a 4Fe—4S ferredoxin). 

Vanadium Peroxidase and nitrogenase activity in some algae and possibly fungi... 

The vanadium nitrogenase from A. vinelandii has the same a2 2 subunit structure as the Mo enzyme. Interestingly, a second VNase has been isolated from A. vinelandii, lacking one of the a subunits and consequently one of the M clusters and half of one of the P clusters. This incomplete a/ 2 variant is still active.I ] VNases in general are less stable than their Mo counterparts, leading to a larger variability and pronounced problems when it comes to crystallisation. 

Iron-vanadium nitrogenase was isolated in 1986. Its nitrogen-reducing activity is 1/3-1/2 of that for molybdenum nitrogenase, and the VFe protein is spectroscopically different from the analogous MoFe protein. There is no X-ray crystal structure of any component of iron-vanadium nitrogenase. 

Aryloxo and thiolato vanadium complexes as chemical models of the active site of vanadium nitrogenase 05CCR(249)2144. 

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