The Azotobacter vinelandii nifL-like gene: nucleotide sequence analysis and regulation of expression.
The nucleotide sequence of the Azotobacter vinelandii nifL-like gene (Av-nifL) was determined. The 1.9 kb sequence shows an open reading frame (ORF) of 1577 bp which encodes a polypeptide of 519 amino acids, with a calculated molecular weight of 57,793. Av-nifL has about 50% homology with the Klebsiella pneumoniae nifL gene (Kp-nifL) at the nucleotide level and a little more than 52% homology at the amino acid level. The N-terminal regions show more homology than the C-terminal regions. As is the case in K. pneumoniae, Av-nifL is located just upstream of the A. vinelandii nifA gene (Av-nifA) and both genes constitute an operon. The expression of Av-nifL, however, seems to be independent of NtrA and NtrC. Furthermore, Av-nifL expression is not autogenously regulated by NifA, unlike the case in K. pneumoniae. The expression of an Av-nifL::lacZ fusion in A. vinelandii is inhibited by novobiocin and coumermycin A, which are inhibitors of DNA gyrase.
Raina
R
R
Genetic Engineering Unit, Jawaharlal Nehru University, New Delhi, India.
Bageshwar
U K
UK
Das
H K
HK
D000595:Amino Acid Sequence; D016948:Azotobacter vinelandii / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D004278:DNA, Superhelical; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004278:DNA, Superhelical; C080989:nifL-like protein, Azotobacter