Phosphotransferase system, IIB component, type 1 (IPR001996)

Short name: PTS_IIB_1

Overlapping homologous superfamilies

Domain relationships



The phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS) [PMID: 8246840, PMID: 2197982] 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 the following: a phosphoryl group from phosphoenolpyruvate (PEP) is transferred to enzyme-I (EI) of PTS which in turn transfers it to a phosphoryl carrier protein (HPr). Phospho-HPr then transfers the phosphoryl group to a sugar-specific permease which consists of at least three structurally distinct domains (IIA, IIB, and IIC) [PMID: 1537788] which can either be fused together in a single polypeptide chain or exist as two or three interactive chains, formerly called enzymes II (EII) and III (EIII).

The first domain (IIA) carries the first permease-specific phoshorylation site, a histidine, which is phosphorylated by phospho-HPr. The second domain (IIB) is phosphorylated by phospho-IIA on a cysteinyl or histidyl residue, depending on the permease. Finally, the phosphoryl group is transferred from the IIB domain to the sugar substrate in a process catalyzed by the IIC domain; this process is coupled to the transmembrane transport of the sugar.

Several PTS permease families are currently recognised, namely, the (i) glucose (including glucoside), (ii) fructose (including mannitol), (iii) lactose (including N,N-diacetylchitobiose), (iv) galactitol, (v) glucitol, (vi) mannose, and (vii) l-ascorbate families [PMID: 16339738].

This entry represents the component IIB of the glucose family of PTS systems (type 1).

GO terms

Biological Process

GO:0009401 phosphoenolpyruvate-dependent sugar phosphotransferase system

Molecular Function

GO:0008982 protein-N(PI)-phosphohistidine-sugar phosphotransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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