Beschreibung:
<jats:p> <jats:bold>A two‐dimensional structural model was devised for the Opc outer membrane protein invasin which contains 10 transmembrane strands and five surface‐exposed loops. One continuous epitope recognized by three monoclonal antibodies was localized to the tip of loop 2 by synthetic peptides and site‐directed mutagenesis while a second, discontinuous epitope recognized by a fourth antibody was localized to loops 4 and 5 by insertion mutagenesis. These monoclonal antibodies are bactericidal and inhibit adhesion and invasion. Most of the T‐cell epitopes defined by Wiertz <jats:italic>et al. </jats:italic>(1996) were localized to the transmembrane strands. Oligonucleotides encoding a foreign epitope (∇) from Semliki Forest virus were inserted into <jats:italic>Bgl</jats:italic>II restriction sites created by site‐directed mutagenesis. The ∇ epitopes inserted in all five predicted loops were recognized on the cell surface of live <jats:italic>Escherichia coli</jats:italic> bacteria by a monoclonal antibody and are exposed while ∇ epitopes in the N‐terminus or three predicted turns were not. The results thus confirm important predictions of the model and define five permissive sites within surface‐exposed loops which can be used to insert foreign epitopes.</jats:bold> </jats:p>