Ganchev Dragomir N, Cobb Nathan J, Surewicz Krystyna, Surewicz Witold K
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA.
Biophys J. 2008 Sep 15;95(6):2909-15. doi: 10.1529/biophysj.108.133108. Epub 2008 Jun 6.
Amyloids are associated with a number of protein misfolding disorders, including prion diseases. In this study, we used single-molecule force spectroscopy to characterize the nanomechanical properties and molecular structure of amyloid fibrils formed by human prion protein PrP90-231. Force-extension curves obtained by specific attachment of a gold-covered atomic force microscope tip to engineered Cys residues could be described by the worm-like chain model for entropic elasticity of a polymer chain, with the size of the N-terminal segment that could be stretched entropically depending on the tip attachment site. The data presented here provide direct information about the forces required to extract an individual monomer from the core of the PrP90-231 amyloid, and indicate that the beta-sheet core of this amyloid starts at residue approximately 164-169. The latter finding has important implications for the ongoing debate regarding the structure of PrP amyloid.
淀粉样蛋白与多种蛋白质错误折叠疾病相关，包括朊病毒疾病。在本研究中，我们使用单分子力谱来表征由人朊病毒蛋白PrP90 - 231形成的淀粉样纤维的纳米力学性质和分子结构。通过将覆盖金的原子力显微镜尖端特异性连接到工程化的半胱氨酸残基获得的力 - 伸长曲线，可以用聚合物链熵弹性的蠕虫状链模型来描述，N末端片段的大小可以根据尖端连接位点进行熵拉伸。此处呈现的数据提供了从PrP90 - 231淀粉样蛋白核心提取单个单体所需力的直接信息，并表明该淀粉样蛋白的β-折叠核心起始于大约164 - 169位残基。后一发现对正在进行的关于PrP淀粉样蛋白结构的辩论具有重要意义。
