Vanadium containing nitrogenases

Kentemich, T., Danneberg, G., Hundeshagen, B. and Bothe, H. (1988) Evidence for the occurrence of the alternative, vanadium-containing nitrogenase in the cyanohacterium Anabaena variabilis. PEMS Microbiol. Lett., 51, 19-24. 

More complicated aggregate structures are found in the vanadium-copper and vanadium-silver species [ViMiS SPh CR ]" (M = Cu or Ag) (133), in which the metal sulfido core is in the shape of a cube [Fig. 14(d)] bulk magnetic susceptibility measurements have shown that there is probably a direct V —V bond within these species. These and related complexes are of interest since a vanadium-containing nitrogenase has been discovered (136). 

DiSpirito A A, Taaffe LR, Lipscomb JD, Hooper AB (1985) A blue copper oxidase from Nitrosomonas europaea. Biochim Biophys Acta 827 320-326 Djebli A, Proctor P, Blake RC Jr, Shoham M (1992) Crystallization and preliminary X-ray crystallographic studies of rusticyanin from Thiobacillus ferrooxidans. J Mol Biol 227 581-582 Dua RD, Bhandan B, Nicholas DJD (1979) Stable isotope studies on the oxidation of ammonia to hydroxylamine by Nitrosomonas europaea. FEBS Lett 106 401-404 Dymond J, Collier RW, Watwood ME (1989) Bacterial mats from Crater Lake, Oregon and their relationship to possible deep-lake hydrothermal venting. Nature 342 673-675 Eady RR (1988) The vanadium-containing nitrogenase of Azotobacter. Biofactors 1 111-116... 

See also Function of Coenzymes, Nitrogenase Reductase (vanadium-containing in Azotobacter)... 

Alternative nitrogenases also exist that lack molybdenum and instead contain either vanadium or no heterometal at all. These nitrogenases are generally less active, less selective and less understood than the Mo-containing nitrogenases. Biophysical and biochemical evidence, ineluding, in particular, cofactor isolation and re-incorporation experiments using MoFe-apoprotein, indicate that the iron-vanadium-eofactor is isostruetural with the well-studied FeMo-cofactor. 

A number of nitrogen-fixing bacteria contain vanadium and it has been shown that in one of these, Azotobacter, there are three distinct nitrogenase systems based in turn on Mo, V and Fe, each of which has an underlying functional and structural similarity.This discovery has prompted a search for models and the brown compound [Na(thf)]+[V(N2)2(dppe)2] (dppe = Pli2PCH2CH2PPh2) has recently been prepared by reduction of VCI3 by sodium naphthalenide... 

An Fe-only nitrogenase has also been isolated from a nifH mutant of Rhodospirillum rubrum and was characterized as an a2/82<% hex-amer containing only iron, no molybdenum or vanadium, with an o 2Fe4S4-containing Fe protein. A factor could be extracted from the FeFe protein into NMF that combined with apo-MoFe protein to form an active enzyme 193). 

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