Characterization of glycoprotein glycan receptors for Escherichia coli F17 fimbrial lectin

Abstract

The specificity of N-acetylglucosamine-binding F17 fimbrial lectin of coli (also called FY or Att25) for the oligosacharide structures was investigated by mannose-resistant hemagglutination inhibition tests and direct binding assays. The linkage position of N-acetylglucosamine influenced its affinity in the preferential order of βt1–3 > β1–6 > β1–4 β > β1–2. Minimal GlcNAc β1–3Gal β1-sequence strongly bound to F17 lectin, whether located in terminal nonreducing position or internally in carbohydrate moieties. F17 lectin specifically interacted with this unit in O-glycosidically linked oligosaccharides of the bovine glycophorins and intestinal mucins. On the contrary, GlcNAc β1- NAsn, GlcNAc β1-6Man β- and GlcNAc β1-4GlcNAc- of N-glycosylated proteins failed to bind to the lectin. Our findings emphasized the presence of multiple F17 mucosal receptor complex in the newborn calf intestines. Furthermore, the density of receptors for F17 fimbrial lectin seemed to depend on the age of the calf and the intestinal segment.