Molecular characterization of the gene coding for major outer membrane protein OmpA from Enterobacter aerogenes

Abstract

The ompA gene from E. aerogenes was subcloned into a low-copy-number plasmid vector and the resultant plasmid, pTU7En, used to study its expression in Escherichia coli K12. Although the gene was strongly expressed and large amounts of OmpA protein were present in the outer membrane, its product was not functionally identical to the E. coli peptide. The E. aerogenes OmpA protein was unable to confer sensitivity to OmpA specific phages of E. coli. When the primary structure of the protein was deduced from the nucleotide sequence of its gene, it was found that 3 domains differed extensively from the corresponding regions of the E. coli protein. As 2 of these are known to be exposed on the cell surface, it was inferred that these alterations are responsible for differences in the biological activity of the 2 proteins.