【作者】 杨靖鸽； 王继乾； 徐海；

【Author】 Jingge Yang;Jiqian Wang;Hai Xu;College of Chemical Engineering,China University of Petroleum(East China);

【机构】 中国石油大学(华东)化学工程学院；

【摘要】 环二肽是由两个氨基酸通过肽键环合形成,是自然界中最小的环肽。由于其存在两个酰胺键,即四个氢键位点,环二肽在强氢键相互作用的驱动下具有高度的自组装倾向。本文报告了不同氨基酸残基对环二肽自组装行为的影响以及组装体的性能。AFM和SEM结果发现不同残基侧链的环二肽可组装形成不同尺寸的纳米纤维,且部分纤维存在左手螺旋形貌。CD结果表明纳米纤维组装体中分子采取β-sheet的二级结构。我们推测在氢键作用力的驱动下环二肽分子逐个堆叠形成纳米纤维,而苯丙氨酸残基的存在会使环二肽纳米纤维在π-π堆积的作用下发生螺旋现象。荧光光谱结果表明不同环二肽组装体具有不同的荧光性能。更多还原

【Abstract】 Cyclic dipeptide is formed by cyclization of two amino acids through amide bonds. It is the smallest cyclic peptide in nature. The two amide bonds, i.e. four hydrogen bond sites, give the cyclic dipeptide a highly self-assembly propensity, mainly driven by the strong hydrogen bonding interaction. We have studied the effects of different amino acid residues on the self-assembly of cyclic dipeptides and the property of the self-assemblies. AFM and SEM results showed that the cyclic dipeptides with different residue side chains could self-assemble into nanofibers of different size, and some nanofibers had left-handed spiral morphology. CD results showed that the molecules in nanofibers adopted β-sheet secondary structure. It was assumed that cyclic dipeptide molecules were stacked one by one to form nanofibers driven by the hydrogen bonding force. Phenylalanine residues caused the formation of twisted nanofibers through π-π stacking. Moreover, the fluorescence spectra showed that different assemblies had different fluorescence properties.更多还原