This domain is found in a wide range of outer membrane proteins, found mainly in Alphaproteobacteria.Examples are the Major Outer Membrane Protein (ompP1) from various strains of Coxiella burnetti, which possesses the typical porin properties: it is heat-modifiable, it has channel activity and is predicted to form a ß-barrel; Omp3b from Brucella abortus and homologs from various Alphaproteobacteria that are believed to be involved in bacterial surface control and host cell interactions. In Pseudomonas aeruginosa, OprH forms an 8-stranded ß-barrel protein with four extracellular loops of unequal size. Using in vivo and in vitro biochemical assays, OprH indeed interacts with LPS in P. aeruginosa outer membranes. In Yersinia pestis the causative agent of plague, the outer membrane protein Ail (Adhesion invasion locus) is one of the most highly expressed proteins on the cell surface.