Figure 3.
Structures of common fucosylated glycans. (A) Synthesis of ABO blood group antigens. The H and Se transferases are a pair of α(1,2)-fucosyltransferases that synthesize the H antigen in a variety of tissues. The ABO locus encodes a glycosyltransferase that further modifies the H antigen. The A allele at the ABO locus encodes an N-acteylgalactosaminyltransferase. The B allele encodes a galactosyltransferase that differs from the A transferase at four amino acid positions. The O allele at the ABO locus encodes a truncated, enzymatically inactive protein. (B) Lewis-related antigens. Circles indicate the immunodominant portion of each antigen. (C) A representative O-linked fucose glycan. Fucose modifies serines or threonine within the broad consensus site shown here, and in Table I. R indicates glycolipid and N- and O-linked glycoprotein precursors. Reprinted from137, with permission.