Antigenic and Molecular Homology of the Ferric Enterobactin Receptor Protein of Escherichia coli

Abstract

The Fe3+ enterobactin receptor protein (81 kDa [kilodalton]) of E. coli O111 was purified by preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and used to raise polyclonal antiserum in rabbits. This antiserum was used in conjunction with the immunoblot technique to examine the degree of antigenic homology of the Fe3+ enterobactin receptor protein among 17 pathogenic and laboratory strains of E. coli. Both the MW and the antigenic properties of the enterobactin receptor were highly conserved. However, the laboratory strain C and a pathogenic enteroinvasive strain, E. coli O164, were unusual in not producing the 81 kDa protein. The antiserum also recognized an 81 kDa protein from Fe-restricted Salmonella typhimurium and an 83 kDa protein from Fe-restricted Klebsiella pneumoniae.