Effects on Molecular Conformation and Anticoagulant Activities of 1,6-Anhydrosugars at the Reducing Terminal of Antithrombin-Binding Octasaccharides Isolated from Low-Molecular-Weight Heparin Enoxaparin
Effects on Molecular Conformation and Anticoagulant Activities of 1,6-Anhydrosugars at the Reducing Terminal of Antithrombin-Binding Octasaccharides Isolated from Low-Molecular-Weight Heparin Enoxaparin
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DOI：
10.1021/jm100771s
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发表时间：
2010-11-25
影响因子：
7.3
通讯作者：
Viskov, Christian
中科院分区：
文献类型：
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作者：
Guerrini, Marco;Elli, Stefano;Viskov, Christian
末端1,6-脱水氨基糖(1,6-anAS)是依诺肝素的典型结构部分，它是低分子量肝素(LMWH)，广泛用于预防和治疗血栓性疾病。在依诺肝素制造过程中，这些修饰的氨基糖是在肝素的β-消除裂解过程中形成的。为了研究末端 anAS 对抗凝血酶 (AT) 结合和 Xa 因子 (FXa) 抑制的影响，从依诺肝素中分离出两种含有修饰的 AT 结合五糖序列的八糖。分别以 N-磺基-1,6-脱水-邻-甘露糖胺和 N-磺基-1,6-脱水-D-葡萄糖胺封端的八糖的分子构象已通过 NMR 实验和对接模拟在不存在和存在 AT 的情况下确定。末端 anAS 残基与 AT 结合区域的总体接触减少，导致对 AT 的亲和力降低以及抗 EXa 活性降低。在缓冲液或血浆环境中测量的抗 FXa 没有显示任何显着差异，表明抗 FXa 的抑制仍然具有特异性和生物学相关性。
Terminal 1,6-anhydro-aminosugars (1,6-anAS) are typical structural moieties of enoxaparin, it low-molecular-weight heparin (LMWH) widely used for prevention and treatment of thrombotic disorders. In the enoxaparin manufacturing process, these modified amino sugars are formed during the beta-eliminative cleavage of heparin. To investigate the effect of terminal anAS on antithrombin (AT) binding and on inhibition of factor Xa (FXa), two octasaccharides containing modified AT-binding pentasaccharide sequences were isolated from enoxaparin. The molecular conformation of the octasaccharides terminating with N-sulfo-1,6-anhydro-o-mannosamine and N-sullo-1,6-anhydro-D-glucosamine, respectively, has been determined both in the absence and presence of AT by NMR experiments and docking simulations. Reduced overall contacts of the terminal anAS residues with the binding region of AT induce a decrease in affinity for AT as well as lower anti-EXa activity. The anti-FXa measured either in buffer or plasma milieu does not show any significant difference, suggesting that the inhibition of anti-FXa remains specific and biologically relevant.