Previous studies of amyloid diseases reported that the aggregating proteins share a similar conserved peptide sequence which can form the cross-β-sheet-containing nanostructures like nanofilaments. The template-assisted self-assembly (TASA) of peptides on inorganic substrates with different hydrophilicity could be an alternative approach to shed light on the fibrillization mechanism of proteins/peptides in vivo. To figure out the effect of interfaces on amyloid aggregation, we herein employed in situ atomic force microscopy (AFM) to investigate the self-assembling of a Parkinson disease-related core peptide sequence (TGV-9) on a hydrophobic liquid–solid interface via real-time observation of the dynamic fibrillization process. The results show that TGV-9 forms one-dimensional nanostructures on the surface of highly ordered pyrolytic graphite (HOPG) with three preferred growth orientations, which are consistent with the atomic lattice of HOPG, indicating an epitaxial growth or TASA. Conversely, the nanostructures formed in bulk solution can be free-standing nanofilaments, and the fibrillization mechanism is different from that on HOPG. These results could not only deepen the understanding of the protein/peptide aggregation mechanism but also benefit for the early diagnosis and clinic treatment of related diseases.

中文翻译：

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原位原子力显微镜对肽TGV-9自组装的比较研究

先前对淀粉样蛋白疾病的研究报道，聚集蛋白具有相似的保守肽序列，可以形成含有交叉β-折叠的纳米结构，如纳米丝。肽在具有不同亲水性的无机底物上的模板辅助自组装（TASA）可能是阐明蛋白质/肽原纤维化机制的另一种方法体内. 为了弄清楚界面对淀粉样蛋白聚集的影响，我们在此采用原位原子力显微镜 (AFM) 通过实时观察动态原纤维化过程来研究帕金森病相关核心肽序列 (TGV-9) 在疏水液-固界面上的自组装。结果表明，TGV-9在高度有序的热解石墨（HOPG）表面形成一维纳米结构，具有三个优选的生长方向，与HOPG的原子晶格一致，表明外延生长或TASA。相反，在本体溶液中形成的纳米结构可以是独立的纳米丝，其原纤化机制与 HOPG 上的不同。这些结果不仅可以加深对蛋白质/肽聚集机制的认识，也有利于相关疾病的早期诊断和临床治疗。