This domain is found in QslA from Pseudomonas aeruginosa. QslA is an antiactivator which binds to the transcription factor LasR, disrupting its dimerization and preventing LasR from binding to target DNA. QslA forms a dimer that interacts with the ligand-binding domain in LasR [1].

1: QsIA disrupts LasR dimerization in antiactivation of bacterial quorum sensing. Fan H, Dong Y, Wu D, Bowler MW, Zhang L, Song H; Proc Natl Acad Sci U S A. 2013;110:20765-20770. PMID:24319092