NifU and NifS are required for the maturation of nitrogenase and cannot replace the function of isc-gene products in Azotobacter vinelandii.
In recent years, it has become evident that [Fe-S] proteins, such as hydrogenase, nitrogenase and aconitase, require a complex machinery to assemble and insert their associated [Fe-S] clusters. So far, three different types of [Fe-S] cluster biosynthetic systems have been identified and these have been designated nif, isc and suf. In the present work, we show that the nif-specific [Fe-S] cluster biosynthetic system from Azotobacter vinelandii, which is required for nitrogenase maturation, cannot functionally replace the isc [Fe-S] cluster system used for the maturation of other [Fe-S] proteins, such as aconitase. The results indicate that, in certain cases, [Fe-S] cluster biosynthetic machineries have evolved to perform only specialized functions.
Johnson
D C
DC
Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061-0346, USA.
Dos Santos
P C
PC
Dean
D R
DR
D016948:Azotobacter vinelandii / Q000201:enzymology / Q000378:metabolism*; D001426:Bacterial Proteins / Q000502:physiology*; D005798:Genes, Bacterial; D005810:Multigene Family; D009591:Nitrogenase / Q000378:metabolism*
D001426:Bacterial Proteins; C088637:NifU protein, Bacteria; C080001:nifS protein, Bacteria; D009591:Nitrogenase