Functional modulation of Escherichia coli RNA polymerase

Abstract

The promoter recognition specificity of Escherichia coli RNA polymerase is modulated by replacement of the σ subunit in the first step and by interaction with transcription factors in the second step. The overall differentiated state of ~2000 molecules of the RNA polymerase in a single cell can be estimated after measurement of both the intracellular concentrations and the RNA polymerase-binding affinities for all seven species of the σ subunit and 100-150 transcription factors. The anticipated impact from this line of systematic approach is that the prediction of the expression hierarchy of ~4000 genes on the E. coli genome can be estimated.