The Crp-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 70-75 amino acids present in transcription regulators of the crp-fnr family, involved in the control of virulence factors, enzymes of aromatic ring degradation, nitrogen fixation, photosynthesis, and various types of respiration. The Crp-Fnr family is named after the first members identified in Escherichia … expand

The Crp-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 70-75 amino acids present in transcription regulators of the crp-fnr family, involved in the control of virulence factors, enzymes of aromatic ring degradation, nitrogen fixation, photosynthesis, and various types of respiration. The Crp-Fnr family is named after the first members identified in Escherichia coli: the well characterised cyclic AMP receptor protein CRP or CAP (catabolite activator protein) and the fumarate and nitrate reductase regulator Fnr. Crp-type HTH domain proteins occur in most bacteria and in chloroplasts of red algae. The DNA-binding HTH domain is located in the C-terminal part; the N-terminal part of the proteins of the Crp-Fnr family contains a nucleotide-binding domain and a dimerization/linker helix occurs in between. The Crp-Fnr regulators predominantly act as transcription activators, but can also be important repressors, and respond to diverse intracellular and exogenous signals, such as cAMP, anoxia, redox state, oxidative and nitrosative stress, carbon monoxide, nitric oxide or temperature [ PUBMED:8441692 PUBMED:14638413 ].