cAMP receptor protein
| CAMP receptor protein | |||||||
|---|---|---|---|---|---|---|---|
 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 | ||||||
| |||||||
cAMP receptor protein (in short CRP, also known as catabolite gene activator protein (in short CAP)) is a regulatory protein in bacteria. This protein binds cAMP, which causes a conformational change that allows the protein to bind tightly to a specific DNA sequence in the promoters of the genes it controls.[1] Binding of the CRP to the promoter regions of these genes is considered as the basic mechanism. [2]The genes regulated by this protein are mostly involved in energy metabolism, such as galactose, citrate, or the PEP group translocation system.[3][4]
1. CAP must be bound to the catabolite, The cyclic AMP (cAMP) helps to activate Glucose transport and inhibits cAMP synthesis AND lactose transport. Catabolite repression can be lifted by adding cAMP to media
2. Galactose regulation • CAP binds cAMP to form CAP-cAMP dimer. • Binding of CAP-cAMP in upstream region of lac operon increases binding of RNA polymerase at promoter • Transcription of lac genes begins. • Lactose also required as inducer to remove repressor protein bound at operator (negative control of lac operon). – Repressor is encoded by lacI gene.
3. Glucose regulates cAMP levels and transport of lactose Phosphotransferase System. a. Enzyme IIAGlc-P donates phosphate to HPr-P, which donates phosphate to glucose during transport. b. Enzyme IIAGlc-P also activates adenylate cyclase for cAMP production, so less available IIAGlc-P equals less cAMP. c. Enzyme IIAGlc binds to lactose permease and blocks uptake of lactose [5]
References
- ^ Harman JG (2001). "Allosteric regulation of the cAMP receptor protein". Biochim. Biophys. Acta. 1547 (1): 1–17. doi:10.1016/S0167-4838(01)00187-X. PMID 11343786.
- ^ Heyduk T, Lee J.C. (1989). "Escherichia coli cAMP receptor protein: evidence for three protein conformational states with different promoter binding affinities". Arch. Biochemistry,. 28 (17): 6914–6924. doi:10.1021.
{{cite journal}}: Check|doi=value (help) - ^ Weickert MJ, Adhya S (1993). "The galactose regulon of Escherichia coli". Mol. Microbiol. 10 (2): 245–51. doi:10.1111/j.1365-2958.1993.tb01950.x. PMID 7934815.
- ^ Bott M (1997). "Anaerobic citrate metabolism and its regulation in enterobacteria". Arch. Microbiol. 167 (2–3): 78–88. doi:10.1007/s002030050419. PMID 9133329.
- ^ Madigan M.t (2012). "Brock Biology of Microorganisms": 230–260.
{{cite journal}}: Cite journal requires|journal=(help); Text "ISBN-13: 978-0-321-64963-8" ignored (help)
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