Protein Domain : Transcription regulator Rrf2-type, conserved site IPR030489

Type	Conserved_site
Description	The rrf2-type HTH domain is a DNA-binding, winged helix-turn-helix (wHTH) domain of about 130 residues present in transcription regulators of the rrf2family. This family of bacterial regulators is named after Desulfovibrio vulgaris rrf2, a regulator of the hmc operon which encodesiron-sulfur-containing proteins as well as other proteins involved in electron transport []. Other rrf2-type HTH proteins are regulators of genes involvedin nitrite or iron metabolism, or nitric oxide detoxification. The N-terminal part of the domain shows similarity to the iclR-type, the gntR-type and marR-type HTH, wherein the DNA-binding HTH motif is followed by a β-hairpin which is called the wing. The C-terminal part of the rrf2-type HTH domain inmost cases contains 3 conserved cysteine residues that may bind an [2Fe-2S] cluster, like in iscR and nsrR [, , , , , ]. The nsrR regulator, which contains annitrogen-oxides-sensing Fe-S cluster that is required for DNA binding, is implicated in denitrification and/or NO detoxification in diverse pathogenicand environmental bacteria. This entry represents a conserved site located in the central part of these proteins that covers the stronger conserved region [], 'the wing', whichstarts directly C-terminal to the 'helix-turn-helix' motif of these proteins.
Short Name	TR_Rrf2-type_CS