Triphenylalanine peptides self-assemble into nanospheres and nanorods that are different from the nanovesicles and nanotubes formed by diphenylalanine peptides
Triphenylalanine peptides self-assemble into nanospheres and nanorods that are different from the nanovesicles and nanotubes formed by diphenylalanine peptides
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三苯丙氨酸肽自组装成纳米球和纳米棒，与二苯丙氨酸肽形成的纳米囊泡和纳米管不同
DOI：
10.1039/c3nr02505e
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发表时间：
2014-01-01
期刊：
影响因子：
6.7
通讯作者：
Wei, Guanghong
中科院分区：
文献类型：
--
作者：
Guo, Cong;Luo, Yin;Wei, Guanghong
在分子水平上理解多肽纳米结构自组装的本质对于合理设计功能生物纳米材料至关重要。最近的实验研究表明，基于三苯丙氨酸(FFF)的多肽可以自组装成固体的板状纳米结构和纳米球，这与以二苯丙氨酸(FF)为基础的多肽形成的空心纳米微囊和纳米管不同。尽管进行了广泛的研究，但FFF和FF纳米结构之间的组装机制和结构差异的分子基础仍然知之甚少。在这项工作中，我们首先利用粗粒度分子动力学模拟研究了FFF纳米结构的组装过程和结构特征，并将其与FF纳米结构进行了比较。我们发现FFF肽自发组装成含有大量β-薄片的固体纳米球和纳米棒，这与FT-IR表征的数百纳米FFF纳米片的结构特征一致。不同于我们之前报道的水填充FF纳米球和纳米管的形成机制，在FFF纳米球和纳米棒的自组装过程中没有观察到中间双分子层。FFF纳米结构中的多肽主要是反平行排列的，这可以形成比FF型纳米结构更大尺寸的β片状结构。相反，FF多肽表现出类脂组装行为，并组装成双层纳米结构。此外，虽然FF和FFF多肽的自组装主要是由侧链-侧链(SC-SC)芳香堆积相互作用驱动的，但主链-主链(MC-MC)相互作用在组装的精细结构的形成中也起着重要作用。MC-MC和SC-SC之间微妙的相互作用导致了这两种多肽形成不同的纳米结构。这些发现为二/三苯丙氨酸多肽组装的结构和自组装途径提供了新的见解，可能有助于设计生物启发的纳米结构。
Understanding the nature of the self-assembly of peptide nanostructures at the molecular level is critical for rational design of functional bio-nanomaterials. Recent experimental studies have shown that triphenylalanine(FFF)-based peptides can self-assemble into solid plate-like nanostructures and nanospheres, which are different from the hollow nanovesicles and nanotubes formed by diphenylalanine(FF)-based peptides. In spite of extensive studies, the assembly mechanism and the molecular basis for the structural differences between FFF and FF nanostructures remain poorly understood. In this work, we first investigate the assembly process and the structural features of FFF nanostructures using coarse-grained molecular dynamics simulations, and then compare them with FF nanostructures. We find that FFF peptides spontaneously assemble into solid nanometer-sized nanospheres and nanorods with substantial beta-sheet contents, consistent with the structural properties of hundred-nanometer-sized FFF nano-plates characterized by FT-IR spectroscopy. Distinct from the formation mechanism of water-filled FF nanovesicles and nanotubes reported in our previous study, intermediate bilayers are not observed during the self-assembly process of FFF nanospheres and nanorods. The peptides in FFF nanostructures are predominantly anti-parallel-aligned, which can form larger sizes of beta-sheet-like structures than the FF counterparts. In contrast, FF peptides exhibit lipid-like assembly behavior and assemble into bilayered nanostructures. Furthermore, although the self-assembly of FF and FFF peptides is mostly driven by side chain-side chain (SC-SC) aromatic stacking interactions, the main chain-main chain (MC-MC) interactions also play an important role in the formation of fine structures of the assemblies. The delicate interplay between MC-MC and SC-SC interactions results in the different nanostructures formed by the two peptides. These findings provide new insights into the structure and self-assembly pathway of di-/tri-phenylalanine peptide assemblies, which might be helpful for the design of bioinspired nanostructures.