Regulation of porin gene expression over a wide range of extracellular pH inEscherichia coliK-12: Influence of atolAmutation

Analysis of porin gene expression as a function of extracellular pH (pHo) showed that ompF and lamB expression passed through a maximum, whereas ompC expression passed through a minimum at pH 8. This pH-dependent control operated at both transcriptional and post-transcriptional levels of ompF, but only at the transcriptional level on ompC. Similar studies carried out with tolA, tolB and excC mutant strains showed that the TolA, TolB and ExcC proteins are involved in the pH regulation of porin genes.