Helix-Turn-Helix DNA binding domain of the BltR transcription regulator
Helix-turn-helix (HTH) multidrug-efflux transporter transcription regulator, BltR (BmrR-like transporter) of Bacillus subtilis, and related proteins; N-terminal domain. Blt, like Bmr, is a membrane protein which causes the efflux of a variety of toxic substances and antibiotics. These regulators are comprised of two distinct domains that harbor the regulatory (effector-binding) site and the active (DNA-binding) site. Their conserved N-terminal domains contain predicted winged HTH motifs that mediate DNA binding, while the C-terminal domains are often unrelated and bind specific coactivator molecules. They share the N-terminal DNA binding domain with other transcription regulators of the MerR superfamily that promote transcription by reconfiguring the spacer between the -35 and -10 promoter elements.