FEATURES

DESCRIPTION

Also known as CRP_ECOLI, crp, cap, csm. A global transcription regulator, which plays a major role in carbon catabolite repression (CCR) as well as other processes. Binds cyclic AMP (cAMP) which allosterically activates DNA binding (to consensus sequence 5'-AAATGTGATCTAGATCACATTT-3') to directly regulate the transcription of about 300 genes in about 200 operons and indirectly regulate the expression of about half the genome. There are 3 classes of CRP promoters; class I promoters have a single CRP-binding site upstream of the RNA polymerase (RNAP)-binding site, whereas in class II promoters the single CRP- and RNAP-binding site overlap, CRP making multiple contacts with RNAP. Class III promoters require multiple activator molecules, including at least one CRP dimer. CRP can act as an activator, repressor, coactivator or corepressor. Induces a severe bend in DNA (about 87 degrees), bringing upstream promoter elements into contact with RNAP. Acts as a negative regulator of its own synthesis as well as for adenylate cyclase (cyaA), which generates cAMP. High levels of active CRP are detrimental to growth (PubMed:16260780). In CCR it prevents expression of genes involved in catabolism of nonpreferred carbon sources when glucose is present. CCR involves cAMP, adenylate cyclase (cyaA), CRP and the EIIA-Glc component of the PTS (crr). In the presence of glucose, EIIA-Glc is dephosphorylated, and does not activate adenylate cyclase, leading to reduced cAMP and thus decreased CRP activity. When glucose is absent cAMP binds to CRP, upregulating expression of genes involved in the consumption of non-glucose carbon sources. Also plays a role in many other processes (see PubMed:22573269)., Among the targets of CRP is the spf gene which encodes the dual-function sRNA Spot 42; spf expression is repressed by CRP (PubMed:2454912). Spot 42 base pairs with and represses expression from a number of mRNAs encoding proteins involved in the uptake and catabolism of nonpreferred carbon sources. CRP and Spot 42 coregulate at least 14 operons involved in cellular metabolism, forming a coherent feedforward loop (PubMed:21292161). Interaction with SpfP, encoded within the Spot 42 RNA, reinforces this feedforward loop (PubMed:35239441). Homodimer, which upon binding cAMP is able to bind DNA. AR1 of the upstream subunit binds to the C-terminus of RNAP subunit RpoA, AR2 of the downstream subunit binds to the N-terminus of RpoA while AR3 binds to sigma-70 (rpoD) (PubMed:11124031, PubMed:12202833, PubMed:1646077, PubMed:1653449, PubMed:19359484, PubMed:19805344, PubMed:19903881, PubMed:2828639, PubMed:2839152, PubMed:6286624, PubMed:8757802, PubMed:8978616, PubMed:9096308, Ref.44). Interacts with SpfP (PubMed:35239441).

EXTERNAL LINKS

crp

DNA-binding transcriptional dual regulator CRP

crp

Molecular Synopsis