Protein Domain : Antitermination protein Q superfamily IPR038500

Type	Homologous_superfamily
Description	This entry consists of antitermination proteins found in bacteriophages, such as protein Q from phage lambda, and some bacterial homologues. Protein Q positively regulates expression of the phage late gene operon by binding to the bacterial host RNA polymerase (RNAP) and modifying it. This protein binds a specific DNA Q-binding element (QBE) and interacts with RNAP. The modified RNAP can read without pausing and through transcription terminators preceding late genes [ , ]. It participates in the lysis-lysogeny decision by activating the expression of the late lytic genes []. The structure of Q from bacteriophage 21 revealed that it forms a torus, that narrows and extends the RNAP RNA-exit channel and extrudes the linked RNA, preventing the formation of pause and terminator hairpins [].
Short Name	Antitermination_sf