Binding specificities of wild-type and cloned Escherichia coli strains that recognize globo-A

Abstract

In this study we compared the specificity for the globoseries of glycolipids of Escherichia coli expressing the O-negative, A-positive (ONAP) adhesin and clones transformed with the pap-like (prs or pap-2) gene cluster. Receptor-active glycolipids were identified by the ability of radiolabeled bacteria to bind to the glycolipids on thin-layer chromatogram plates. The ONAP adhesin and pap-like clones bound with high affinity to the globo-A and Forssman glycolipids.The ONAP strains did not recognize other glycolipids of the globoseries. In contrast, the pap-like clones also showed weak binding to globotriaosylceramide and reacted weakly with Galα1→4Galβ-latex beads. We suggest that the pap-like and ONAP adhesins recognize an epitope shared by the globo-A and Forssman structures, e.g., terminal GalNAcα1→3 bound to Galα1→4Galβ-containing glycolipids.