RtcR is a sigma54-dependent enhancer binding protein [1] that activates transcription of the rtcBA operon. The product of the rtcA gene is an RNA 3'-terminal phosphate cyclase [2]. This domain is found at the N terminus of the RtcR sequence. RtcR, and other sigma54-dependent activators, contain Pfam:PF00158 in the central region of the protein sequence.

1: Domain Architectures of sigma(54)-Dependent Transcriptional Activators. Studholme DJ, Dixon R; J Bacteriol 2003;185:1757-1767. PMID:12618438

2: Characterization of the Escherichia coli RNA 3'-terminal phosphate cyclase and its sigma54-regulated operon. Genschik P, Drabikowski K, Filipowicz W; J Biol Chem 1998;273:25516-25526. PMID:9738023