Helix-Turn-Helix DNA binding domain of the BmrR transcription regulator
Helix-turn-helix (HTH) multidrug-efflux transporter transcription regulator, BmrR and YdfL of Bacillus subtilis, and related proteins; N-terminal domain. Bmr is a membrane protein which causes the efflux of a variety of toxic substances and antibiotics. BmrR is comprised of two distinct domains that harbor a regulatory (effector-binding) site and an active (DNA-binding) site. The conserved N-terminal domain contains a winged HTH motif that mediates DNA binding, while the C-terminal domain binds coactivating, toxic compounds. BmrR shares 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.