Kato Haruhito, Kaneta Noboru, Nii Susumu, Kobayashi Kazukiyo, Fukui Nobuyuki, Shinohara Hisanori, Nishida Yoshihiro
Molecular Design & Engineering, Graduate School of Engineering, Nagoya University Chikusa-ku, Nagoya 464-8603, Japan.
Chem Biodivers. 2005 Sep;2(9):1232-41. doi: 10.1002/cbdv.200590093.
The bis(alpha-D-mannopyranosyl)-[60]fullerene conjugate 3 was prepared by thermal coupling of C60 and either 2-azidoethyl 2,3,4,6-tetra-O-acetyl- or 2,3;4,6-di-O-isopropylidene-alpha-D-mannopyranoside (Scheme). Compound 3 was found to readily self-assemble. Dynamic-light-scattering (DLS) and atomic-force microscopy (AFM) experiments supported that the amphiphilic compound gives rise to nano-sized supramolecular structures during sugar deprotection (Ac-group removal) performed in MeOH/CH2Cl2 solution. Encapsulation studies with an aqueous suspension of 3 showed that the self-assembling structure envelopes Ba2+ and the fluorescent dye Acridine Red during its formation, which indicates that it resembles a bilayer vesicle or an unadulterated liposome with an inner hollow space. In addition to this notable property, the unique molecular geometry of the spatially arranged mannosyl surface residues of 3 gives rise to strong binding of the carbohydrate-recognizing lectin Con A. Hence, the polar amphiphilic end of 3 mimics the structure of 3,6-branched tri-alpha-D-mannoside (6; Fig. 3), a natural ligand of the Con A protein.
双（α-D-甘露吡喃糖基）-[60]富勒烯共轭物3是通过C60与2-叠氮基乙基2,3,4,6-四-O-乙酰基-α-D-甘露吡喃糖苷或2,3;4,6-二-O-异亚丙基-α-D-甘露吡喃糖苷进行热偶联制备的（方案）。发现化合物3易于自组装。动态光散射（DLS）和原子力显微镜（AFM）实验表明，在甲醇/二氯甲烷溶液中进行糖脱保护（去除乙酰基）时，这种两亲性化合物会形成纳米级超分子结构。对3的水悬浮液进行的包封研究表明，自组装结构在形成过程中包裹Ba2+和荧光染料吖啶红，这表明它类似于具有内部中空空间的双层囊泡或纯净脂质体。除了这一显著特性外，3中空间排列的甘露糖基表面残基的独特分子几何结构导致了与碳水化合物识别凝集素伴刀豆球蛋白A的强烈结合。因此，3的极性两亲端模仿了3,6-分支三-α-D-甘露糖苷（6；图3）的结构，后者是伴刀豆球蛋白A蛋白的天然配体。
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