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; and proteins from various species of Pseudomonas, of which a 3D structure suggests a ß-barrel structure of 8 stands.