HPr(Ser) kinase/phosphorylase, N-terminal (IPR011126)

Short name: Hpr_kin/Pase_Hpr_N

Overlapping homologous superfamilies

Domain relationships



Two-component signal transduction systems enable bacteria to sense, respond, and adapt to a wide range of environments, stressors, and growth conditions [PMID: 16176121]. Some bacteria can contain up to as many as 200 two-component systems that need tight regulation to prevent unwanted cross-talk [PMID: 18076326]. These pathways have been adapted to response to a wide variety of stimuli, including nutrients, cellular redox state, changes in osmolarity, quorum signals, antibiotics, and more [PMID: 12372152]. Two-component systems are comprised of a sensor histidine kinase (HK) and its cognate response regulator (RR) [PMID: 10966457]. The HK catalyses its own auto-phosphorylation followed by the transfer of the phosphoryl group to the receiver domain on RR; phosphorylation of the RR usually activates an attached output domain, which can then effect changes in cellular physiology, often by regulating gene expression. Some HK are bifunctional, catalysing both the phosphorylation and dephosphorylation of their cognate RR. The input stimuli can regulate either the kinase or phosphatase activity of the bifunctional HK.

A variant of the two-component system is the phospho-relay system. Here a hybrid HK auto-phosphorylates and then transfers the phosphoryl group to an internal receiver domain, rather than to a separate RR protein. The phosphoryl group is then shuttled to histidine phosphotransferase (HPT) and subsequently to a terminal RR, which can evoke the desired response [PMID: 11934609, PMID: 11489844].

This entry represents the N-terminal region of Hpr Serine/threonine kinase PtsK. This kinase is the sensor in a multicomponent phosphorelay system in control of carbon catabolic repression in bacteria [PMID: 11904409]. This kinase is unusual in that it recognises the tertiary structure of its target and is a member of a novel family unrelated to any previously described protein phosphorylating enzymes [PMID: 11904409]. X-ray analysis of the full-length crystalline enzyme from Staphylococcus xylosus at a resolution of 1.95 A shows the enzyme to consist of two clearly separated domains that are assembled in a hexameric structure resembling a three-bladed propeller. The blades are formed by two N-terminal domains each, and the compact central hub assembles the C-terminal kinase domains [PMID: 9570401].

GO terms

Biological Process

GO:0000160 phosphorelay signal transduction system
GO:0006109 regulation of carbohydrate metabolic process

Molecular Function

GO:0005524 ATP binding
GO:0000155 phosphorelay sensor kinase activity
GO:0004672 protein kinase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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