1.B.4 The Brucella-Rhizobium Porin (BRP) Family
The porin proteins in the BRP family are found in the Agrobacterium, Bartonella, Brucella, Mesorhizobium and Rhizobium genuses and are likely to be found in other closely related genera. Brucella species have two homologous outer membrane porins, Omp2a and Omp2b, encoded by two closely linked genes oriented in oppostie directions. Omp2 proteins exist in many size variants due to multiple gene conversions between the two homologous genes that lead to chimeric proteins. These variants show different permeability to sugars as well as different ion conductivities (Paquet et al, 2001). This family is also called the Omp2 family in SwissProt.