Mode of molecular recognition of L-fucose by fucose-binding legume lectins

Recognition of cell surface carbohydrate moieties by lectins plays a vital role in many a biological process. Fucosyated residues are often implicated as key recognition markers in many cellular processes. In particular, the aspects of molecular recognition of fucose by fucose-bindinglectins UEA 1 and LTA pose a special case because no crystal structure of these lectins is available. The study was conducted to elucidate the process of recognition of l-fucose by UEA1 and LTA by correlating structure-based sequence alignment and other available biochemical/biophysical data. The study points out that the mode of recognition of l-fucose is coordinated by the invariant triad of residues the asparagine 137, glycine 105, and aspartate 87. The major hydrophobic stacking residue in this case is the tyrosine 220. The study also reiterates the key role of the conserved triad of residues in the combining site which is a common feature for all legume lectins whose crystal structures are known.