Chemoenzymatic synthesis and structural characterization of 2-O-sulfated glucuronic acid-containing heparan sulfate hexasaccharides.
Heparan sulfate and heparin are highly sulfated polysaccharides that consist of a repeating disaccharide unit of glucosamine and glucuronic or iduronic acid. The 2-O-sulfated iduronic acid (IdoA2S) residue is commonly found in heparan sulfate and heparin; however, 2-O-sulfated glucuronic acid (GlcA2S) is a less abundant monosaccharide (∼<5% of total saccharides). Here, we report the synthesis of three GlcA2S-containing hexasaccharides using a chemoenzymatic approach. For comparison purposes, additional IdoA2S-containing hexasaccharides were synthesized. Nuclear magnetic resonance analyses were performed to obtain full chemical shift assignments for the GlcA2S- and IdoA2S-hexasaccharides. These data show that GlcA2S is a more structurally rigid saccharide residue than IdoA2S. The antithrombin (AT) binding affinities of a GlcA2S- and an IdoA2S-hexasaccharide were determined by affinity co-electrophoresis. In contrast to IdoA2S-hexasaccharides, the GlcA2S-hexasaccharide does not bind to AT, confirming that the presence of IdoA2S is critically important for the anticoagulant activity. The availability of pure synthetic GlcA2S-containing oligosaccharides will allow the investigation of the structure and activity relationships of individual sites in heparin or heparan sulfate.
Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Rm 303, Beard Hall, Chapel Hill, NC 27599, USA.
Po-Hung
PH
Hsieh
Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Rm 303, Beard Hall, Chapel Hill, NC 27599, USA.
Yongmei
Y
Xu
Food & Drug Administration, CDER (Center for Drug Evaluation and Research), Division of Pharmaceutical Analysis, 645 S Newstead Avenue, St. Louis, MO 63110, USA.
David A
DA
Keire
Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Rm 303, Beard Hall, Chapel Hill, NC 27599, USA jian_liu@unc.edu.
Jian
J
Liu
D002236:Carbohydrate Conformation; D005965:Glucuronates / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006497:Heparan Sulfate / Q000096:biosynthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis* / Q000737:chemistry; D015238:Sulfotransferases / Q000378:metabolism*
D005965:Glucuronates; D006497:Heparan Sulfate; D009844:Oligosaccharides; D015238:Sulfotransferases; C046100:glucuronic acid 2-sulfate
chemoenzymatic synthesis; heparan sulfate; heparin; oligosaccharides; sulfotransferase