Insertion of peptides into cell-surface-exposed areas of the Escherichia coli OmpA protein does not interfere with export and membrane assembly

Peptides, 21 amino acids (aa) in length, were inserted into cell-surface-exposed areas of the Escherichia coli outer membrane protein, OmpA, corresponding to aa positions 70 or 154 or at both sites simultaneously. The corresponding hybrid proteins were exported and normally assembled in the outer membrane. The results of protease-accessibility experiments are compatible with the presence of the peptides at the cell surface.