The nucleotide sequence of the nitrogen regulation genentrBand theglnA-ntrBCintergenic region ofKlebsiella pneumoniae

The nucleotide sequence of the Klebsiella pneumoniae ntrB gene and the glnA-ntrBC intergenic region has been determined. NtrB encodes a 38,409 Dalton polypeptide with a potential DNA-binding domain between residues 67 and 86. This N-terminal domain may play a role in the co-operative control of ntr-regulated promoters by the ntrB and ntrC products. Mapping of in vivo transcripts with S1 nuclease identified three transcripts in the glnA-ntrBC intergenic region. Two transcripts originate upstream of glnA; one reading through into ntrBC and one terminating at a sequence resembling a rho-independent terminator between glnA and ntrBC. A third transcript originates from the ntrBC promoter which has a consensus binding site for the ntrC product in the -10 region. Comparison of the glnA-ntrBC intergenic sequences from K. pneumoniae, Escherichia coli and Salmonella typhimurium has identified a number of conserved features and some significant differences.