Abstract
Specific protein interactions in E. coli outer membrane were analyzed using chemical cross-linking with truly cleavable reagents and symmetrical 2-dimensional sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The major outer membrane proteins formed crosslinked complexes. These include multimers of [phage] .lambda. receptor, protein I, II*, III and the free form of lipoprotein. Lipoprotein was also cross-linked to proteins II* and III. The identity of many of these complexes was verified using appropriate mutants missing the proteins in question. No new protein interactions were detected in the mutants even when 3 of the major proteins were missing. Proteins II*, III and the free form of lipoprotein could also be cross-linked to the peptidoglycan layer of the cell wall.