Bacteriophage T4, MotA, transcription regulator N-terminal (IPR015198)

Short name: Phage_T4_MotA_Tscrpt_reg_N

Overlapping homologous superfamilies

Domain relationships



Transcription factor MotA is required for the activation of middle promoters in Bacteriophage T4, in addition to phage T4 co-activator AsiA, and sigma-70-containing Escherichia coli RNA polymerase. Phage T4 middle promoters have the sigma70 -10 DNA element, but not the -35 element; instead, they have a MotA box at -30 to which the transcription factor MotA binds [PMID: 16996538]. MotA and AsiA interact with the C-terminal of sigma70 (region 4), which normally binds the -35 element and the beta-flap, thereby diverting sigma70 away from host promoters that require -35 element-binding to phage T4 middle promoters.

Transcription factor MotA has two domains: an N-terminal domain required for binding to sigma70, and a C-terminal domain required for binding to the -30 MotA box element in the phage T4 middle promoter. This entry represents the N-terminal (activation) domain of MotA factors that binds sigma70. The N-terminal domain adopts an almost completely alpha-helical topology, with five alpha-helices and a short, two-stranded, beta-ribbon. Four alpha helices (alpha1, alpha3, alpha4 and alpha5) are amphipathic and pack their hydrophobic surfaces around the central helix alpha2 [PMID: 9155025].

Contributing signatures

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