1.B.64 The Brucella Omp2 Porin (B-Omp2) Family
In Brucella abortus, a gene encoding a major cell envelope protein, omp2, is duplicated within a short segment of the large chromosomal DNA (Marquis and Ficht 1993). The genes, omp2a or omp2b, were expressed in Escherichia coli. Both gene products localized to the outer membrane. Initial rates of transport of [14C]maltose and growth rates in the presence of maltodextrins of defined size indicated an increased hydrophilic permeability of transformants expressing omp2a. These cells grow on maltotetraose, molecular mass of 667 Da. Activity consistent with the formation of pores has been demonstrated in transformants expressing both genes, but Omp2a forms trimers while Omp2b forms monomers (Mobasheri et al. 1997; Roussel et al. 2012; Jain et al. 2014) . A 16 stranded beta barrel porin has been proposed (Paquet et al. 2000).
The generaiized reaction demonstrated for Brucella Omp2a is:
Sugars (out) → Sugars (in).