Many pathogenic Gram-negative bacteria use type III secretion systems (T3SS) to deliver effector proteins into the host cell cytosol and facilitate the infectious process. The effector protein ExoU from Pseudomonas aeruginosa, one of the most aggressive toxins injected by a T3SS, has four distinct domains. The chaperone-binding domain consists of two separate regions, a N-terminal region and a middle subdomain (this entry). The latter shows a mostly alpha-helical structure [1-3].

1: Structure of the type III secretion effector protein ExoU in complex with its chaperone SpcU. Halavaty AS, Borek D, Tyson GH, Veesenmeyer JL, Shuvalova L, Minasov G, Otwinowski Z, Hauser AR, Anderson WF; PLoS One. 2012;7:e49388. PMID:23166655

2: Structural basis of cytotoxicity mediated by the type III secretion toxin ExoU from Pseudomonas aeruginosa. Gendrin C, Contreras-Martel C, Bouillot S, Elsen S, Lemaire D, Skoufias DA, Huber P, Attree I, Dessen A; PLoS Pathog. 2012;8:e1002637. PMID:22496657

3: A novel phosphatidylinositol 4,5-bisphosphate binding domain mediates plasma membrane localization of ExoU and other patatin-like phospholipases. Tyson GH, Halavaty AS, Kim H, Geissler B, Agard M, Satchell KJ, Cho W, Anderson WF, Hauser AR; J Biol Chem. 2015;290:2919-2937. PMID:25505182