| Primary Identifier | IPR019887 | Type | Domain |
| Short Name | Tscrpt_reg_AsnC/Lrp_C |
| description | The many bacterial transcription regulation proteins which bind DNA through a'helix-turn-helix' motif can be classified into subfamilies on the basis ofsequence similarities. One such family is the AsnC/Lrp subfamily []. The Lrp family of transcriptional regulators appears to be widely distributed among bacteria andarchaea, as an important regulatory system of the amino acid metabolism and related processes []. Members of the Lrp family are small DNA-binding proteins with molecular masses of around15kDa. Target promoters often contain anumber of binding sites that typically lack obvious inverted repeat elements, and to which binding isusually co-operative. LrpA from Pyrococcus furiosus is the first Lrp-like protein to date of which a three-dimensional structurehas been solved. In the crystal structure LrpA forms an octamer consistingof four dimers. The structure revealed that the N-terminal part of the protein consists of ahelix-turn-helix (HTH) domain, a fold generally involved in DNA binding.The C terminus of Lrp-like proteins has a β-fold, where the two α-helices are located at one side of the four-stranded antiparallel β-sheet.LrpA forms a homodimer mainly through interactions between the β-strands of this C-terminaldomain, and an octamer through further interactions between the second α-helix and fourth β-strandof the motif. Hence, the C-terminal domain of Lrp-like proteins appears tobe involved in ligand-response and activation [].This entry represents the C-terminal regulatory ligand binding domain of the transcription regulator AsnC/Lrp. Structurally this domain has a dimeric alpha/beta barrel fold [, ]. This domain binds almost exclusively amino acids, but also 4-hydroxyphenylpyruvate and kynurenine (Matilla et. al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043). |
