DNA architecture and transcriptional regulation of the Escherichia coli penicillin amidase (pac) gene

The transcriptional regulation of Escherichia coli ATCC11105 penicillin ami dase (pac) gene was studied by modifying DNA sequences responsible For prom oter activation by cyclic AMP receptor protein (CRP). The nucleotide sequen ce of the 5'-flanking region of the pac gene contains putative tandem CRP b inding sites positioned at -69/-70 and at -111/-112 with respect to the tra nscriptional start site. Our results obtained with either point mutations o r insertion or deletion mutants (each of which rotated the helix structure at the CRP binding site one-half turn) showed significant decrease of penic illin amidase (PA) activity, suggesting the CRP as a major activator. In th is study, the evidence fur the importance of spacing between tandem binding sites for CRP as well as for their location related to the promoter core s equence has been provided. Involvement of integration host factor (IHF) as an additional regulatory protein in the pac gene transcription regulation w as also analyzed. It is shown that activation of the pac gene transcription is elevated by IHF. (C) 2001 Elsevier Science B.V. All rights reserved.