Cyclic AMP Receptor Protein-Dependent Activation of the Escherichia coli acsP2 Promoter by a Synergistic Class III Mechanism

摘要: ABSTRACT The cyclic AMP receptor protein (CRP) activates transcription of the Escherichia coli acs gene, which encodes an acetate-scavenging enzyme required for fitness during periods carbon starvation. Two promoters direct acs, distal acsP1 and proximal acsP2. In this study, we demonstrated that acsP2 can function as major promoter showed by in vitro studies CRP facilitates “focusing” RNA polymerase to We proposed from a synergistic class III mechanism. Consistent with proposal, binds two sites, I II. Induction expression absolutely I, while optimal both locations these DNA sites (centered at positions −69.5 −122.5, respectively) suggest interacts through interactions. support hypothesis, requires surfaces C-terminal domain α subunit holoenzyme (α-CTD), is known participate interactions: activating region 1 287, 265, 261 determinants α-CTD. Other surface-exposed residues α-CTD contributed transcription, suggesting may interact least one other than CRP.