Difucosylated

Difucosylated refers to glycan-containing molecules that bear two fucose residues in their carbohydrate portion. Fucose is a deoxyhexose sugar that is commonly linked to other sugars by α-linkages, most often α1-2, α1-3, α1-4, or α1-6. In difucosylated glycans, two fucose units are present, either on the same glycan arm or on separate branches, and may appear on N-linked or O-linked glycans. Common patterns include core fucosylation (α1-6 to the reducing-end GlcNAc) together with an antennal fucose, or the occurrence of two fucoses within an antigenic motif such as the difucosylated Lewis B structure (Fucα1-2Galβ1-3(Fucα1-4)GlcNAc).

Difucosylation can influence interactions with fucose-binding proteins, including selectins and various lectins, and thereby modulate cell adhesion, immune recognition, and pathogen interactions. Changes in difucosylation patterns have been reported in normal physiology and in disease states, including cancer, where altered fucosylation of glycans is observed.

Analytical characterization relies on glycomic and glycoproteomic methods, such as mass spectrometry, exoglycosidase sequencing, and lectin-based assays, to determine the number and linkage of fucose residues. Because difucosylation describes a structural feature rather than a single motif, precise structural elucidation is important for linking it to function.