Murasato Kazuya, Matsuura Kazunori, Kimizuka Nobuo
Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Moto-oka 744, Nishi-ku, Fukuoka 819-0395, Japan.
Biomacromolecules. 2008 Mar;9(3):913-8. doi: 10.1021/bm701302p. Epub 2008 Feb 21.
A novel C3 symmetric peptide conjugate "Wheel-FKFE" consisting of three beta-sheet-forming peptides with wheel-like arrangement is developed, and the morphology of self-assembled peptide conjugates in aqueous solutions is observed at various pH. The CD spectra of Wheel-FKFE show the formation of beta-sheet structures in pH 6.9 phosphate buffer, whereas random structures are formed in aqueous HCl (pH 3.3) and NaOH (pH 11) solutions. In transmission electron microscopy, nanofibers with a uniform width of 3-4 nm and lengths of several micrometers are observed in pH 6.9 phosphate buffer, whereas nanorods with the width of several nanometers and the length of several tens of nanometers are observed for that of aqueous HCl (pH 3.3) and NaOH (pH 11) solutions. The uniform width (3-4 nm) of the fibers observed in neutral solution indicates formation of columnar self-assembly of Wheel-FKFEs. The fluorescence spectrum of polarity sensitive dye, sodium 8-anilino-1-naphthalenesulfonate (ANS), in the presence of Wheel-FKFE fibers revealed that the polarity inside the fibers corresponds to that of acetone, indicating that the internal space of the fibers possesses medium hydrophobic environment.
一种新型的由三个具有轮状排列的β-折叠形成肽组成的C3对称肽缀合物“Wheel-FKFE”被开发出来，并在不同pH值下观察了其在水溶液中自组装肽缀合物的形态。Wheel-FKFE的圆二色光谱显示在pH 6.9的磷酸盐缓冲液中形成了β-折叠结构，而在盐酸水溶液（pH 3.3）和氢氧化钠水溶液（pH 11）中形成了无规结构。在透射电子显微镜下，在pH 6.9的磷酸盐缓冲液中观察到宽度均匀为3 - 4 nm、长度为几微米的纳米纤维，而在盐酸水溶液（pH 3.3）和氢氧化钠水溶液（pH 11）中观察到宽度为几纳米、长度为几十纳米的纳米棒。在中性溶液中观察到的纤维均匀宽度（3 - 4 nm）表明Wheel-FKFEs形成了柱状自组装。在Wheel-FKFE纤维存在的情况下，极性敏感染料8-苯胺基-1-萘磺酸钠（ANS）的荧光光谱显示纤维内部的极性与丙酮的极性相当，表明纤维的内部空间具有中等疏水环境。
