Helix-Turn-Helix DNA binding domain of the MerR-like transcription regulators YyaN and YraB
Putative helix-turn-helix (HTH) MerR-like transcription regulators of Bacillus subtilis, YyaN and YraB, and related proteins; N-terminal domain. Based on sequence similarity, these proteins are predicted to function as transcription regulators that mediate responses to stress in eubacteria. They belong to the MerR superfamily of transcription regulators that promote transcription of various stress regulons by reconfiguring the operator sequence located between the -35 and -10 promoter elements. A typical MerR regulator is comprised of distinct domains that harbor the regulatory (effector-binding) site and the active (DNA-binding) site. Their N-terminal domains are homologous and contain a DNA-binding winged HTH motif, while the C-terminal domains are often dissimilar and bind specific coactivator molecules such as metal ions, drugs, and organic substrates.