Loading Pathway...
Error: Pathway image not found.
Hide
Pathway Description
Operon: Carnitine Operon
Escherichia coli
Signaling Pathway
The caiTABCDE operon is activated under anaerobic conditions to facilitate the anaerobic metabolism of carnitine. The operon is primarily activated by the ArcA protein, which is phosphorylated by ArcB in response to a reduced quinone pool under low oxygen conditions. This phosphorylated ArcA (ArcA-P) binds upstream of the operon, initiating transcription. Additionally, the CaiF transcriptional activator is induced by the cAMP-CRP complex, which forms when intracellular cAMP levels rise in response to low glucose availability, further enhancing transcription of the operon. The operon encodes proteins like CaiT, a membrane antiporter for L-carnitine, CaiA, CaiB, CaiC, and CaiD, which catalyze various reactions necessary for carnitine metabolism, ensuring efficient energy production under anaerobic conditions.
References
Operon: Carnitine Operon References
Kleber HP: Bacterial carnitine metabolism. FEMS Microbiol Lett. 1997 Feb 1;147(1):1-9.
Pubmed: 9037756
Eichler K, Bourgis F, Buchet A, Kleber HP, Mandrand-Berthelot MA: Molecular characterization of the cai operon necessary for carnitine metabolism in Escherichia coli. Mol Microbiol. 1994 Sep;13(5):775-86.
Pubmed: 7815937
Buchet A, Eichler K, Mandrand-Berthelot MA: Regulation of the carnitine pathway in Escherichia coli: investigation of the cai-fix divergent promoter region. J Bacteriol. 1998 May;180(10):2599-608.
Pubmed: 9573142
Highlighted elements will appear in red.
Highlight Compounds
Highlight Proteins
Enter relative concentration values (without units). Elements will be highlighted in a color gradient where red = lowest concentration and green = highest concentration. For the best results, view the pathway in Black and White.
Visualize Compound Data
Visualize Protein Data
Settings