This domain is found in ExsE present in Pseudomonas aeruginosa. ExsE forms part of the ExsACDE signaling cascade which acts as an important regulatory switch that ensures timely expression of the Type III secretion system (T3SS) and so plays a critical role in facilitating infection. Prior to host-cell contact, the T3SS is inactive and ExsE and Type III Secretion Chaperone (ExsC) form a stable complex. ExsC forms a compact homodimer and ExsE wraps around one face of this dimer [1].

1: Analysis of the crystal structure of the ExsC.ExsE complex reveals distinctive binding interactions of the Pseudomonas aeruginosa type III secretion chaperone ExsC with ExsE and ExsD. Vogelaar NJ, Jing X, Robinson HH, Schubot FD; Biochemistry. 2010;49:5870-5879. PMID:20536183