Self-assembly and Mechanism of Surfactant-like Peptide A6KA6K

A diploid A(6)KA(6)K of surfactant-like peptide A(6)K 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 A(6)KA(6)K was mainly random coil and minor alpha-helix, which was 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 A(6)K reported previously, the longer peptide A(6)KA(6)K containing 14 amino acids could form 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.