Trivalent α-D-mannoside clusters as inhibitors of type-1 fimbriae-mediated adhesion of Escherichia coli:: structural variation and biotinylation

Structural modifications of trivalent cluster mannosides are presented to further elucidate the ligand preferences of the type-1 fimbrial lectin of Escherichia coli. Two types of variations are performed, either regarding the aglycone part of cluster mannosides of type 2, leading to 27, or altering the spacer lengths of mannosyl clusters of type 1, leading to clusters 20-22. Biotinylation of the cluster mannoside with the highest affinity to the type-1 fimbrial lectin is also shown (33). Testing of the inhibitory potencies of the synthesised cluster glycosides as inhibitors of mannose-specific (type-1 fimbriae-mediated) binding of E. coli to mannan in an enzyme-linked immunosorbent assay (ELISA) suggests that a structural preorganisation as given in cluster 2a can be favourably combined with greater spacer flexibility as in cluster 22.