Structure/function relationships in OmpR and other winged-helix transcription factors

Response regulators are the output component of two-component regulatory systems, the predominant form of signal transduction systems utilized by prokaryotes. The majority of response regulators function as transcription factors, yet detailed descriptions of their mechanisms of DNA binding and its consequences are lacking. Versatility in the modes of DNA binding is evident with winged helix-turn-helix proteins, raising doubts that mechanisms of DNA binding will be generalizable among members of the family. The current focus of some of the research efforts aimed at understanding activation and DNA binding by response regulators is highlighted in this review.