This domain is found at the C-terminal end of bacterial transcriptional regulators, including RolR from Corynebacterium glutamicum (Swiss:Q8NR95), which is involved in aromatic catabolism. This signal-receiving domain shows an all-alpha-helical fold. It is found associated with Pfam:PF00440, responsible for DNA-binding [1].

1: Crystal structures of the transcriptional repressor RolR reveals a novel recognition mechanism between inducer and regulator. Li DF, Zhang N, Hou YJ, Huang Y, Hu Y, Zhang Y, Liu SJ, Wang DC; PLoS One. 2011;6:e19529. PMID:21559286