Homologous Superfamily

PRD domain superfamily (IPR036634)

Short name: PRD_sf

Overlapping entries


Transcriptional antiterminators and activators containing phosphoenolpyruvate: sugar phosphotransferase system (PTS) regulation domains (PRDs) form a class of bacterial regulatory proteins whose activity is modulated by phosphorylation. These regulators stimulate the expression of genes and operons involved in carbohydrate metabolism.

PRD-containing proteins are involved in the regulation of catabolic operons in Gram+ and Gram- bacteria [PMID: 1732212, PMID: 9045813] and are often characterised by a short N-terminal effector domain that binds to either RNA (CAT-RBD for antiterminators, IPR004341) or DNA (for activators), and a duplicated PRD module which is phosphorylated on conserved histidines by the sugar phosphotransferase system (PTS) in response to the availability of carbon source. The phosphorylations are thought to modify the stability of the dimeric proteins and thereby the RNA- or DNA-binding activity of the effector domain [PMID: 11751049, PMID: 11733988, PMID: 11447120].

PRDs are characterised by the presence of a duplicated regulatory module of ~100 residues that can be reversibly phosphorylated on histidyl residues by the PTS. PRDs in transcriptional antiterminators and activators are PTS regulatory targets that are (de)phosphorylated in response to the availability of carbon sources [PMID: 9202047, PMID: 9663674, PMID: 11751049, PMID: 11447120, PMID: 15699035].

The PRD domain comprises one and often two highly conserved histidines. It forms a compact bundle comprising five helices (alpha1-alpha5). The core of the PRD module consists of two pairs of antiparallel helices making an angle of ~60 degrees. The first pair contains the antiparallel helices alpha1 and alpha4, while the second pair contains alpha2 and alpha5. The third helix (alpha3) is oriented perpendicularly to alpha5 at the periphery of the bundle. The helices are connected by loops of varying length [PMID: 11751049, PMID: 11447120, PMID: 15699035].

GO terms

Biological Process

GO:0006355 regulation of transcription, DNA-templated

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

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