title: Transcription activation by catabolite activator protein (CAP).
abstract: Transcription activation by Escherichia coli catabolite activator protein (CAP) at each of two classes of simple CAP-dependent promoters is understood in structural and mechanistic detail. At class I CAP-dependent promoters, CAP activates transcription from a DNA site located upstream of the DNA site for RNA polymerase holoenzyme (RNAP); at these promoters, transcription activation involves protein-protein interactions between CAP and the RNAP alpha subunit C-terminal domain that facilitate binding of RNAP to promoter DNA to form the RNAP-promoter closed complex. At class II CAP-dependent promoters, CAP activates transcription from a DNA site that overlaps the DNA site for RNAP; at these promoters, transcription activation involves both: (i) protein-protein interactions between CAP and RNAP alpha subunit C-terminal domain that facilitate binding of RNAP to promoter DNA to form the RNAP-promoter closed complex; and (ii) protein-protein interactions between CAP and RNAP alpha subunit N-terminal domain that facilitates isomerization of the RNAP-promoter closed complex to the RNAP-promoter open complex. Straightforward combination of the mechanisms for transcription activation at class I and class II CAP-dependent promoters permits synergistic transcription activation by multiple molecules of CAP, or by CAP and other activators. Interference with determinants of CAP or RNAP involved in transcription activation at class I and class II CAP-dependent promoters permits "anti-activation" by negative regulators. Basic features of transcription activation at class I and class II CAP-dependent promoters appear to be generalizable to other activators.
authors.affiliation: School of Biosciences, The University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: S
authors.initials: S
authors.lastname: Busby
authors.forename: R H
authors.initials: RH
authors.lastname: Ebright
mesh_terms: D002373:Cyclic AMP Receptor Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: D002373:Cyclic AMP Receptor Protein; D012321:DNA-Directed RNA Polymerases