Identification of the promoter of the Pseudomonas gene coding for carboxypeptidase G2.

A 213-bp region of noncoding DNA upstream of the ATG start codon of the Pseudomonas carboxypeptidase G2 (CPG2) structural gene has been shown to contain the CPG2 promoter. The mRNA start point (+1) on the DNA sequence has been identified by mapping the 5' end of the CPG2 transcript. The identified promoter region contains a -10 region (TATAAG) that closely resembles the Escherichia coli consensus sequence (TATAAT), but has no easily recognisable -35 region. The lack of homology in the -35 region explains why this particular pseudomonad gene is poorly expressed in E. coli. Similar sequence differences may turn out to be the cause of the generally observed inefficient expression of Pseudomonas genes in E. coli. The promoter region also carries a sequence (CTGGCACTCGAATTGCT) that closely matches the consensus nif promoter sequence (CTGGPyAPyPuNNNNTTGCA) of Klebsiella pneumoniae and Rhizobium, and a similar sequence (ATGGCATGGCGGTTGCT) found in the promoter region of the xylABC operon of the TOL plasmid of Pseudomonas putida.