This RNA binding domain is found at the amino terminus of transcriptional antitermination proteins such as BglG, SacY and LicT. These proteins control the expression of sugar metabolising operons in Gram+ and Gram- bacteria. This domain has been call ...
This RNA binding domain is found at the amino terminus of transcriptional antitermination proteins such as BglG, SacY and LicT. These proteins control the expression of sugar metabolising operons in Gram+ and Gram- bacteria. This domain has been called the CAT (Co-AntiTerminator) domain. It binds as a dimer [1] to short Ribonucleotidic Anti-Terminator (RAT) hairpin, each monomer interacting symmetrically with both strands of the RAT hairpin [4]. In the full-length protein, CAT is followed by two phosphorylatable PTS regulation domains (Pfam:PF00874) that modulate the RNA binding activity of CAT. Upon activation, the dimeric proteins bind to RAT targets in the nascent mRNA, thereby preventing abortive dissociation of the RNA polymerase from the DNA template [2].
The PRD domain (for PTS Regulation Domain), is the phosphorylatable regulatory domain found in bacterial transcriptional antiterminator such as BglG, SacY and LicT, as well as in activators such as MtlR and LevR. The PRD is phosphorylated on one or t ...
The PRD domain (for PTS Regulation Domain), is the phosphorylatable regulatory domain found in bacterial transcriptional antiterminator such as BglG, SacY and LicT, as well as in activators such as MtlR and LevR. The PRD is phosphorylated on one or two conserved histidine residues. PRD-containing proteins are involved in the regulation of catabolic operons in Gram+ and Gram- bacteria and are often characterised by a short N-terminal effector domain that binds to either RNA (CAT-RBD for antiterminators Pfam:PF03123) or DNA (for activators), and a duplicated PRD module which is phosphorylated by the sugar phosphotransferase system (PTS) in response to the availability of carbon source. The phosphorylations modify the conformation and stability of the dimeric proteins and thereby the RNA- or DNA-binding activity of the effector domain. The structure of the LicT PRD domains has been solved in both the active (pdb:1h99, [2]) and inactive state (pdb:1tlv [4]), revealing massive structural rearrangements upon activation.
