Seeding-dependent propagation and maturation of amyloid fibril conformation.
Seeding-dependent propagation and maturation of amyloid fibril conformation.
复制标题
DOI：
10.1016/j.jmb.2005.07.061
复制
发表时间：
2005-09
影响因子：
5.6
通讯作者：
Kei-ichi Yamaguchi;Satoshi Takahashi;T. Kawai;H. Naiki;Y. Goto
中科院分区：
文献类型：
--
作者：
Kei-ichi Yamaguchi;Satoshi Takahashi;T. Kawai;H. Naiki;Y. Goto
淀粉样蛋白原纤维的最新研究集中在多种淀粉样蛋白形式的存在下，甚至与一种蛋白质和它们的繁殖播种，导致构象记忆。为了建立淀粉样纤维这些关键特征的结构基础，我们使用了β2-微球蛋白的淀粉样蛋白生成片段Ser 20-Lys 41（K3），β2-微球蛋白是一种负责透析相关淀粉样变性的蛋白质。在20%（v/v）2，2，2-三氟乙醇和10 mM HCl（pH ≥ 2）中，K3肽形成两种淀粉样纤维f218和f210，圆二色谱和傅立叶变换红外光谱测定β折叠的量不同。原子力显微镜观察表明，β折叠（f210）含量较高的纤维较细、较长。两种原纤维都通过接种进行复制，显示了原纤维构象的模板依赖性繁殖。然而，在重复自接种后，f218原纤维逐渐转化为f210原纤维，揭示了构象成熟。观察到的成熟可以完全解释为两个原纤维的竞争性繁殖。淀粉样纤维的成熟可能在淀粉样变性的发生发展过程中起一定作用。
Recent studies of amyloid fibrils have focused on the presence of multiple amyloid forms even with one protein and their propagation by seeding, leading to conformational memory. To establish the structural basis of these critical features of amyloid fibrils, we used the amyloidogenic fragment Ser20–Lys41 (K3) of β2-microglobulin, a protein responsible for dialysis-related amyloidosis. In 20% (v/v) 2,2,2-trifluoroethanol and 10mM HCl (pH ∼2), K3 peptide formed two types of amyloid-like fibrils, f218 and f210, differing in the amount of β-sheet as measured by circular dichroism spectroscopy and Fourier transform infrared spectroscopy. Atomic force microscopy showed that the fibril with a larger amount of β-sheet (f210) is thinner and longer. Both fibrils were reproduced by seeding, showing the template-dependent propagation of a fibril's conformation. However, upon repeated self-seeding, f218 fibrils were gradually transformed into f210 fibrils, revealing the conformational maturation. The observed maturation can be explained fully by a competitive propagation of two fibrils. The maturation of amyloid fibrils might play a role during the development of amyloidosis.