Lipopolysaccharide structure required for in vitro trimerization of Escherichia coli OmpF porin.

Deep rought mutants, which produce very defective lipopolysaccharides, are unable to export normal levels of porins into the outer membrane. In this study, we showed that lipopolysaccharides from such mutants were also unable to facilitate the trimerization, in vitro, of monomeric OmpF porin secreted by spheroplasts of Escherichia coli B/r. In contrast, lipopolysaccharides containing most or all of the core oligosaccharides were able to facilitate trimerization.