Cyanovirin-N (CV-N) is a cyanobacterial lectin with antiviral activity towards HIV and several other viruses. Here, we identify mannoside hydroxyl protons that are hydrogen bonded to the protein backbone of the CV-N domain B binding site, using NMR spectroscopy. For the two carbohydrate ligands Manα(1→2)ManαOMe and Manα(1→2) Manα(1→6)ManαOMe five hydroxyl protons are involved in hydrogen-bonding networks. Comparison with previous crystallographic results revealed that four of these hydroxyl protons donate hydrogen bonds to protein backbone carbonyl oxygens in solution and in the crystal. Hydrogen bonds were not detected between the side chains of Glu41 and Arg76 with sugar hydroxyls, as previously proposed for CV-N binding of mannosides. Molecular dynamics simulations of the CV-N/Manα(1→2)Manα(1→6)ManαOMe complex confirmed the NMR-determined hydrogen-bonding network. Detailed characterization of CV-N/mannoside complexes provides a better understanding of lectin-carbohydrate interactions and opens up to the use of CV-N and similar lectins as antiviral agents.

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NMR和MD模拟揭示的蛋白质-碳水化合物氢键网络的详细图片

Cyanovirin-N (CV-N) 是一种蓝藻凝集素，对 HIV 和其他几种病毒具有抗病毒活性。在这里，我们使用 NMR 光谱鉴定了与 CV-N 结构域 B 结合位点的蛋白质骨架氢键合的甘露糖苷羟基质子。对于两个碳水化合物配体 Manα(1→2)Manα O Me 和 Manα(1→2) Manα(1→6)Manα OMe 五个羟基质子参与氢键网络。与之前的晶体学结果比较表明，这些羟基质子中的四个向溶液和晶体中的蛋白质骨架羰基氧提供氢键。Glu41 和 Arg76 的侧链与糖羟基之间未检测到氢键，如先前提出的用于甘露糖苷的 CV-N 结合。CV-N/Manα(1→2)Manα(1→6)Manα O Me 复合物的分子动力学模拟证实了 NMR 确定的氢键网络。CV-N/甘露糖苷复合物的详细表征提供了对凝集素-碳水化合物相互作用的更好理解，并为使用 CV-N 和类似的凝集素作为抗病毒剂开辟了道路。