Kato N, Aiba H, Mizuno T
Laboratory of Molecular Microbiology, School of Agriculture, Nagoya University, Japan.
FEMS Microbiol Lett. 1996 Jun 1;139(2-3):175-80. doi: 10.1111/j.1574-6968.1996.tb08199.x.
The OmpR protein is a positive regulator specific for the Escherichia coli ompF and ompC genes. This protein functions in a phosphorylation-dependent manner through a presumed interaction with RNA polymerase. We previously isolated OmpR mutants which were suggested to be defective in transcription activation, but not in DNA binding (the so-called positive control (PC) mutant). In this study we isolated mutants of the alpha-subunit of RNA polymerase which can suppress one of the putative PC mutants of OmpR. A crucial amino acid substitution was identified as [V264G] in the alpha-subunit, which is located in the helix H1 of the C-terminal domain, which has been claimed, based on mutational and structural analyses, to be involved in the interaction with other positive regulators including the well-characterized cAMP receptor protein.
