Rationally designed chemoenzymatic synthesis of heparan sulfate oligosaccharides with neutralizable anticoagulant activity and low severe complications.

The identification of enzymes involved in biosynthesis of heparan sulfate (HS) and heparin and their successful application in chemoenzymatic synthesis have provided great impetus to rationally design well-defined oligosaccharides as ideal alternatives to animal-derived heterogeneous heparin anticoagulants clinically to treat clotting disorders. Herein, we revisited the substrate specificity of recombinant 2-O-sulfotransferases produced in different expression systems for the highly efficient chemoenzymatic synthesis of HS oligosaccharides containing the rare 2-O-sulfated GlcA (GlcA2S) residues, followed by further assembly into the highly sulfated HS dodecasaccharide (12-mer) and decasaccharide (10-mer) containing the antithrombin-binding domain and the trisulfated disaccharide (GlcA2S-GlcNS6S) units rarely found in natural heparin. The GlcA2S-containing HS 10-mer demonstrated both the effectively reversible anticoagulant activity similar to that of unfractionated heparin and the lower potential risk for life-threatening heparin-induced thrombocytopenia compared with enoxaparin, indicating its promising prospect as the next-generation HS/heparin-like anticoagulant therapeutics.