表面活性剂类多肽A6KA6K的自组装及机理研究

为了研究表面活性剂类多肽疏水链段长度及亲疏水氨基酸比例对其自组装结构的影响，本文设计了一种表面活性剂类多肽A6K的二倍体A6KA6K。圆二色谱分析表明的二级结构主要为无规卷曲结构并伴有少量的α-螺旋；透射电子显微镜和动态光散射分析表明，其在水溶液中能自组装形成纳米囊泡状结构。芘荧光分子探针研究表明自组装体存在疏水微区域将芘分子包裹在其中，证明了这种多肽在溶液中可形成胶束类的自组装体，并计算了其临界胶束浓度。相比已报道的表面活性剂类肽A6K，本文设计的肽序列A6KA6K由于在较长疏水链段区域中存在亲水性氨基酸K，对疏水相互作用有影响，使得含有14个氨基酸的肽自组装形成纳米囊泡状结构。

Self-assembly and Mechanism of Surfactant-like Peptide A_6KA_6K

A diploid A6KA6K of surfactant-like peptide A6K was designed to study the influence on the length and ratio of the hydrophilic and hydrophobic segments in the peptide self-assembly. The secondary structure of the A6KA6K was mainly random coil and minor α-helix, which characterized by circular dichroism. The results observed by transmission electron microscopy and dynamic light scattering revealed that the peptide could self-assemble to form nanovesicles in aqueous solution. Pyrene probe fluorescence analysis indicated this peptide could form hydrophobic domains in which pyrene molecules were imbedded and undergo self-assembly in the form of micelles. The critical micelle concentration of the peptide was also calculated. Compared with the surfactant peptide A6K reported previously, the longer peptide A6KA6K containing 14 amino acids could formed nanovesicles through self-assembly, because the introduction of a hydrophilic amino acid into the hydrophobic segment of the peptide influenced the hydrophobic interaction of the peptide.