Structure of 4-F-GlcNAc and potential sites of its incorporation.

(A) Structure of 2-acetamido-1,3,6-tri-O-acetyl-4-fluoro-D-glucopyranose (4-F-GlcNAc). The carbons on the pyranose ring are indicated numerically, starting with the anomeric carbon 1, which forms a glycosidic bond with the acceptor sugar in a β (up) or α (down) position. (B-C) Potential sites of 4-F-GlcNAc incorporation into poly-N-acetyllactosamine chains and into carbohydrate selectin-binding determinants. The large black arrows indicate the potential points of blockage or chain termination. Symbols: fucose (Fuc), galactose (Gal), N-acetylneuraminic acid (NANA), andN-acetylglucosamine (GlcNAc).