Helix-Turn-Helix DNA binding domain of putative HspR-like transcription regulators
Putative helix-turn-helix (HTH) transcription regulator HspR-like proteins. Unlike the characterized HspR, these proteins have a C-terminal domain with putative metal binding cysteines (MBC). Heat shock protein regulators (HspR) have been shown to regulate expression of specific regulons in response to high temperature or high osmolarity in Streptomyces and Helicobacter, respectively. These proteins 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. A typical MerR regulator is comprised of 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 dissimilar C-terminal domains bind specific coactivator molecules.