Hayashi Tomohiro, Sano Ken-Ichi, Shiba Kiyotaka, Iwahori Kenji, Yamashita Ichiro, Hara Masahiko
Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8502, Japan.
Langmuir. 2009 Sep 15;25(18):10901-6. doi: 10.1021/la901242q.
The interactions of ferritins fused with a Ti-recognizing peptide (RKLPDA) and their mutants with titanium oxide substrates were explored with an atomic force microscope (AFM). The amino acid sequence of the peptide was systematically modified to elucidate the role of each amino acid residue in the specific interaction. Force measurements revealed a clear correlation among the sequences in the N-terminal domain of ferritin, surface potentials, and long-range electrostatic interactions. Measurements of adhesion forces clearly revealed that hydrogen bonds take part in the specific binding as well as the electrostatic interaction between charged residues and surface charges of Ti oxides. Moreover, our results indicated that not only the charged and polar residues but also a neutral residue (proline) govern the strength of the specific binding, with the order of the residues also being significant. These results demonstrate that the local structure of the peptide governs the special arrangement of charged residues and strongly affects the strength of the bindings.
利用原子力显微镜（AFM）研究了与钛识别肽（RKLPDA）融合的铁蛋白及其突变体与氧化钛底物的相互作用。对该肽的氨基酸序列进行了系统修饰，以阐明每个氨基酸残基在特异性相互作用中的作用。力测量揭示了铁蛋白N端结构域中的序列、表面电位和长程静电相互作用之间存在明显的相关性。粘附力测量清楚地表明，氢键参与了特异性结合以及带电残基与氧化钛表面电荷之间的静电相互作用。此外，我们的结果表明，不仅带电和极性残基，而且中性残基（脯氨酸）也决定了特异性结合的强度，残基的顺序也很重要。这些结果表明，肽的局部结构决定了带电残基的特殊排列，并强烈影响结合强度。
