Multivalent ligands for the mannose-specific lectin on type 1 fimbriae of Escherichia coli: syntheses and testing of trivalent α-D-mannoside clusters
The syntheses of the triantennary cluster α-D-mannosides 16, 19, 23 and 24 and their capacities to inhibit mannose-dependent binding of E. coli HB 101 (pPKl4) are described. The cluster glycosides are formed by glycosylation of tris-(3-hydroxypropyl)nitromethane 13, and by linking of suitable mannoside derivatives via amide and thiourea bonds to tris-(2-carboxyethyl)nitromethane 17 and tris-(2-aminoethyl)amine 20. Functionalized mannosides are attached to the core molecules at the 6-position of the sugar ring to allow variation of the introduced aglycone moieties in order to compare their effects on the inhibitory potencies of the derived mannoside clusters. The 6-peptide-bridged cluster mannoside 19 displays the highest binding potency towards the type 1 fimbrial lectin of E. coli as tested by inhibition agglutination tests and ELISA.