Biophysics Program, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109, United States.
National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States.
J Phys Chem Lett. 2023 Aug 31;14(34):7644-7649. doi: 10.1021/acs.jpclett.3c02009. Epub 2023 Aug 21.
Intermediates along the fibrillation pathway are generally considered to be the toxic species responsible for the pathologies of amyloid diseases. However, structural studies of these species have been hampered by heterogeneity and poor stability under standard aqueous conditions. Here, we report a novel methodology for producing stable, on-pathway oligomers of the human type-2 diabetes-associated islet amyloid polypeptide (hIAPP or amylin) using the mechanical forces associated with magic angle spinning (MAS). The species were a heterogeneous mixture of globular and short rod-like species with significant β-sheet content and the capability of seeding hIAPP fibrillation. We used MAS nuclear magnetic resonance to demonstrate that the nature of the species was sensitive to sample conditions, including peptide concentration, ionic strength, and buffer. The methodology should be suitable for studies of other aggregating systems.
纤维形成途径中的中间体通常被认为是导致淀粉样变性疾病病理学的毒性物质。然而，由于这些物质的异质性和在标准水相条件下的稳定性差，对它们的结构研究一直受到阻碍。在这里，我们报告了一种使用与魔角旋转（MAS）相关的机械力生产稳定的、与途径相关的人 2 型糖尿病相关胰岛淀粉样多肽（hIAPP 或胰岛淀粉样多肽）的新型方法。这些物质是具有显著β-折叠含量和能够引发 hIAPP 纤维形成的球形和短棒状物质的混合物。我们使用 MAS 核磁共振证明，物种的性质对样品条件敏感，包括肽浓度、离子强度和缓冲液。该方法应该适用于其他聚集系统的研究。
