Instantaneous inclusion of a polynucleotide and hydrophobic guest molecules into a helical core of cationic β-1,3-glucan polysaccharide
Instantaneous inclusion of a polynucleotide and hydrophobic guest molecules into a helical core of cationic β-1,3-glucan polysaccharide
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DOI：
10.1021/ja0684343
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发表时间：
2007-04-04
影响因子：
15
通讯作者：
Shinkai, Seiji
中科院分区：
文献类型：
--
作者：
Ikeda, Masato;Hasegawa, Teruaki;Shinkai, Seiji
我们通过“点击化学”成功地在凝胶多糖（CUR）的C6位上定量、选择性地引入了铵阳离子基团，所得的阳离子凝胶多糖（CUR-N+）在水中表现出良好的溶解性。 ORD 研究表明，CUR-N+ 采用单链结构，与水中 β-1,3-葡聚糖多糖的右旋三链螺旋结构不同。研究表明，CUR-N+与聚合物客体分子的聚合物复合物，例如聚胞苷酸（poly(C)）、全甲基十硅烷（PMDS）和单壁碳纳米管（SWNT），只需将它们与水混合并进行超声处理即可轻松获得。通过 UV-vis、CD 光谱测量以及 AFM 和 TEM 观察对所得 CUR-N+-poly(C) 复合物进行表征，表明它们具有化学计量的纳米纤维结构。根据这些实验结果以及我们之前的研究（例如，参考文献 6 和 23），我们提出络合将由以下因素的协同作用驱动：(1) C2 位的 OH 基团与胞嘧啶环的氢键位点之间的氢键相互作用（参考文献 6d），(2) 铵阳离子和磷酸根阴离子之间的静电相互作用（参考文献 23），以及 (3) 背景疏水相互作用。此外，复合的多核苷酸链对酶水解表现出很强的抵抗力。同样，通过光谱测量和显微镜观察证实了 CUR-N+ 在水中的 PMDS 和 SWNT 分散以及复合物的纤维结构。 CUR-N+ 的这些结合特性可以在水中自发进行，与裂褶多糖 (SPG) 的结合特性明显不同，后者不可避免地需要一个变性-复性过程，该过程对应于由 DMSO 或碱诱导的三链转化为单链以包含聚合物客体分子。
We succeeded in the quantitative and selective introduction of an ammonium cationic group into the C6 position of Curdlan (CUR) by "Click Chemistry", and the obtained cationic Curdlan (CUR-N+) showed good solubility in water. ORD studies suggested that CUR-N+ adopts a single-stranded structure, different from a right-handed, triple-stranded helical structure of beta-1,3-glucan polysaccharides in water. It has been revealed that the polymeric complexes of CUR-N+ with polymeric guest molecules, such as polycytidylic acid (poly(C)), permethyldecasilane (PMDS), and single-walled carbon nanotubes (SWNTs), can be easily obtained by just mixing them in water with sonication. The characterization of the resultant CUR-N+-poly(C) complexes by UV-vis, CD spectroscopic measurements, and AFM and TEM observations revealed that they have stoichiometric, nanosized fibrous structures. From these experimental results as well as our precedent studies (e.g., refs 6 and 23), we propose that the complexation would be driven by the cooperative action of (1) the hydrogen-bonding interaction between the OH group at the C2 position and hydrogen-bonding sites of the cytosine ring (ref 6d), (2) the electrostatic interaction between the ammonium cation and the phosphate anion (ref 23), as well as (3) the background hydrophobic interaction. In addition, the complexed polynucleotide chain showed a strong resistance against enzymatic hydrolysis. Likewise, the dispersion of PMDS and SWNTs in water by CUR-N+ and the fibrous structures of the complexes were confirmed by spectroscopic measurements as well as microscopic observations. These binding properties of CUR-N+, which can proceed spontaneously in water, clearly differ from those of schizophyllan (SPG), which inevitably require a denature-renature process corresponding to a conversion of a triple strand to single strands induced by DMSO or base for inclusion of polymeric guest molecules.