The structure of the promoter and amino terminal region of the pH 2.5 acid phosphatase structural gene (appA) of E. coli: a negative control of transcription mediated by cyclic AMP

Abstract

The regulatory and promoter regions of the gene for acid phosphatase of optimum pH 2.5 (appA) of Escherichia coli has been characterized by constructing appA-lacZ protein fusions. Monitoring of beta-galactosidase activity showed that the cloned fragment harbored a region that was responsible for a negative control of transcription mediated by the cAMP-cAMP receptor (CAP) complex. The nucleotide sequence of the segment was determined. A region containing a putative CAP binding site, overlapping the -10 region of the promoter was found. Deletion analysis around the promoter region, using appA-lacZ protein fusions substantiated the hypothesis for a role of the 'consensus' sequence in the negative control mediated by cyclic AMP. In addition, the coding sequence revealed the likely existence of a signal peptide similar to the one found for other exported proteins, upstream from the phosphatase protein sequence.