The solute selectivity of porin pores of Escherichia coli and Salmonella typhimurium.

: The solute selectivity of porin pores of Escherichia coli and Salmonella typhimurium was examined using vesicle membranes reconstituted from phospholipids and purified porin trimers. OmpE- and 34K-porin-pores allowed a preferential diffusion of phosphorylated and/or negatively charged compounds. They allowed the diffusion of positively charged solutes reasonably well. OmpF- and 35K-porin-pores favored the diffusion of positively charged solutes a little more than negatively charged solutes. OmpC- and 36K-porin-pores showed poor diffusibility to all solute tested. B-porins from E. coli B formed highly efficient pores for the diffusion of both positively and negatively charged solutes. On the basis of these observations, possible mechanisms of solute selectivity were discussed.