PMID:3457004

Citation	Robinson, AC, Burgess, BK and Dean, DR (1986) Activity, reconstitution, and accumulation of nitrogenase components in Azotobacter vinelandii mutant strains containing defined deletions within the nitrogenase structural gene cluster. J. Bacteriol. 166:180-6
Abstract	The Azotobacter vinelandii genes encoding the nitrogenase structural components are clustered and ordered: nifH (Fe protein)-nifD (MoFe protein alpha subunit)-nifK (MoFe protein beta subunit). In this study various A. vinelandii mutant strains which contain defined deletions within the nitrogenase structural genes were isolated and studied. Mutants deleted for the nifD or nifK genes were still able to accumulate significant amounts of the unaltered MoFe protein subunit as well as active Fe protein. Extracts of such nifD or nifK deletion strains had no MoFe protein activity. However, active MoFe protein could be reconstituted by mixing extracts of the mutant strains. These results establish an approach for the purification of the individual MoFe protein subunits. Mutants lacking either or both of the MoFe protein subunits were still able to synthesize the iron-molybdenum cofactor (FeMo-cofactor), indicating that in A. vinelandii the FeMo-cofactor is preassembled and inserted into the MoFe protein. In contrast, a mutant strain lacking both the Fe protein and the MoFe protein failed to accumulate any detectable FeMo-cofactor. The further utility of specifically altered A. vinelandii strains for the study of the assembly, structure, and reactivity of nitrogenase is discussed.
Links	PubMed PMC214574
Keywords	Azotobacter/enzymology; Chromosome Deletion; Genes; Nitrogenase/analysis; Nitrogenase/biosynthesis; Nitrogenase/genetics; Oxidoreductases
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
AZOVI:NIFD		GO:0016612: molybdenum-iron nitrogenase complex	ECO:0000315:		C		Table 1, Figure 5	complete CACAO 2319
AZOVI:NIFK		GO:0016612: molybdenum-iron nitrogenase complex	ECO:0000315:		C		Table 1, Figure 5	complete CACAO 2320

References

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