This domain is found at the N terminus of a subset of sigma54-dependent transcriptional activators that are involved in regulation of flagellar motility e.g. FleQ in Pseudomonas aeruginosa. It is clearly related to Pfam:PF00072, but lacks the conserved aspartate residue that undergoes phosphorylation in the classic two-component system response regulator (Pfam:PF00072).

1: FleQ, the major flagellar gene regulator in Pseudomonas aeruginosa, binds to enhancer sites located either upstream or atypically downstream of the RpoN binding site. Jyot J, Dasgupta N, Ramphal R; J Bacteriol 2002;184:5251-5260. PMID:12218010

2: Interaction of the antiactivator FleN with the transcriptional activator FleQ regulates flagellar number in Pseudomonas aeruginosa. Dasgupta N, Ramphal R; J Bacteriol 2001;183:6636-6644. PMID:11673434

3: fleN, a gene that regulates flagellar number in Pseudomonas aeruginosa. Dasgupta N, Arora SK, Ramphal R; J Bacteriol 2000;182:357-364. PMID:10629180

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