Phosphotransferase system, HPr serine phosphorylation site (IPR002114)

Short name: PTS_HPr_Ser_P_site


The phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS) is a major carbohydrate transport system in bacteria. The PTS catalyzes the phosphorylation of incoming sugar substrates concomitant with their translocation across the cell membrane. The general mechanism of the PTS is as follows: a phosphoryl group from phosphoenolpyruvate (PEP) is transferred to Enzyme I (EI) of the PTS which in turn transfers it to a phosphoryl carrier protein (HPr). Phospho-HPr then transfers the phosphoryl group to a sugar- specific permease complex (enzymes EII/EIII).

HPr is a small cytoplasmic protein, which in some bacteria is found as a domain in a larger protein that includes a EIII(Fru) (IIA) domain and in some cases also a EI domain IPR000032. HPr is a component of the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS) major carbohydrate transport system in bacteria [PMID: 8246840, PMID: 2197982].

There is a conserved histidine in the N terminus of HPr IPR001020, which serves as an acceptor for the phosphoryl group of EI. In the central part of HPr there is a conserved serine, which in Gram-positive bacteria only, is phosphorylated by an ATP-dependent protein kinase; a process which probably plays a regulatory role in sugar transport.

The sequence around both phosphorylation sites are well conserved and can be used as signature patterns for HPr proteins or domains. This signature identifies the serine phosporylation site.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns