CAMP receptor protein | |||||||
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![]() Structure of the E. coli Cyclic AMP Receptor Protein. | |||||||
Identifiers | |||||||
Symbol | CRP | ||||||
Alt. symbols | CAP | ||||||
NCBI gene | 947867 | ||||||
PDB | 1I5Z | ||||||
RefSeq | NP_417816.1 | ||||||
UniProt | P0ACJ8 | ||||||
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cAMP receptor protein (CRP; also known as catabolite activator protein, CAP) is a regulatory protein in bacteria.
CRP protein binds cyclic adenosine monophosphate (cAMP), which causes a conformational change that allows CRP to bind tightly to a specific DNA site in the promoters of the genes it controls. [1] [2] CRP then activates transcription through direct protein–protein interactions with RNA polymerase. [1] [2]
The genes regulated by CRP are mostly involved in energy metabolism, such as galactose, citrate, or the PEP group translocation system. [3] [4] In Escherichia coli, CRP can regulate the transcription of more than 100 genes.
The signal to activate CRP is the binding of cyclic AMP. Binding of cAMP to CRP leads to a long-distance signal transduction from the N-terminal cAMP-binding domain to the C-terminal domain of the protein, which is responsible for interaction with specific sequences of DNA. [5]
At "Class I" CRP-dependent promoters, CRP binds to a DNA site located upstream of core promoter elements and activates transcription through protein–protein interactions between "activating region 1" of CRP and the C-terminal domain of RNA polymerase alpha subunit. [1] [2] [6] At "Class II" CRP-dependent promoters, CRP binds to a DNA site that overlaps the promoter -35 element and activates transcription through two sets of protein–protein interactions: (1) an interaction between "activating region 1" of CRP and the C-terminal domain of RNA polymerase alpha subunit, and (2) an interaction between "activating region 2" of CRP and the N-terminal domain of RNA polymerase alpha subunit. [1] [2] At "Class III" CRP-dependent promoters, CRP functions together with one or more " co-activator" proteins. [1] [2]
At most CRP-dependent promoters, CRP activates transcription primarily or exclusively through a "recruitment" mechanism, in which protein–protein interactions between CRP and RNA polymerase assist binding of RNA polymerase to the promoter. [1]