Abstract: Bacteria have metabolism regulation systems that allow cells to selectively assimilate a preferred compound among a mixture of several potential carbon sources, at the same time inhibiting the use of non-perferred carbon sources. This process is known as carbon catabolite repression (CCR). Current studies have revealed three different systems to be involved in catabolite repression: CbrAB/Crc, CyoABCDE and PTSNtr. CbrAB/Crc system is composed of two component system CbrA/CbrB, non-coding RNA and Crc protein, which can regulate gene transcription of non-preferred carbon sources through modulating the level of free Crc. CyoABCDE system contains several terminal oxidases, which control non-preferred carbon sources through coordinating the composition of the electron transport chain. PTSNtr system is comprised of PtsP protein, PtsO protein and PtsN protein, which act on CCR through the phosphorylation of PtsN protein. In this paper, we summarize the regulation mechanisms of CCR in Pseudomonas.

Key words: carbon catabolite repression, Pseudomonas, CbrAB/Crc, CyoABCDE, PTSNtr