PEP group translocation

[6][7] The phosphotransferase system is involved in transporting many sugars into bacteria, including glucose, mannose, fructose and cellobiose.

[9] In the process of glucose PTS transport specific of enteric bacteria, PEP transfers its phosphoryl to a histidine residue on EI.

Finally, EIIB phosphorylates glucose as it crosses the plasma membrane through the transmembrane enzyme II C (EIIC), forming glucose-6-phosphate.

In many bacteria, there are four different sets of IIA, IIB, and IIC proteins, each specific for a particular sugar (glucose, mannitol, mannose, and lactose/chitobiose).

For example, at low glucose concentrations phosphorylated EIIA accumulates and this activates membrane-bound adenylate cyclase.

Thus, in addition to being an efficient way to import substrates into the bacterium, the PEP group translocation system also links this transport to regulation of other relevant proteins.

The glucose PTS system in E. coli and B. subtilis . The pathway can be read from right to left, with glucose entering the cell and having a phosphate group transferred to it by EIIB. The mannose PTS in E. coli has the same overall structure as the B. subtilis glucose PTS, i.e. the IIABC domains are fused into one protein.
In Serratia marcescens .