Nucleotide sequence and mutational analysis of the vnfENX region of Azotobacter vinelandii.

摘要: The nucleotide sequence (3,600 bp) of a second copy nifENX-like genes in Azotobacter vinelandii has been determined. These are located immediately downstream from vnfA and have designated vnfENX. vnfENX appear to be organized as single transcriptional unit that is preceded by potential RpoN-dependent promoter. While the nifEN thought evolutionarily related nifDK, vnfEN more closely than either vnfDK, or anfDK. Mutant strains (CA47 CA48) carrying insertions vnfE vnfN, respectively, able grow diazotrophically molybdenum (Mo)-deficient medium containing vanadium (V) (Vnf+) lacking both Mo V (Anf+). However, double mutant (strain DJ42.48) which contains deletion an insertion unable Mo-sufficient Mo-deficient with without V. This suggests NifE NifN substitute for VnfE VnfN when mutationally inactivated. AnfA not required expression vnfN-lacZ fusion, even though this fusion expressed under Mo- V-deficient diazotrophic growth conditions.