Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
Institute for Molecular Science (IMS), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan.
Int J Mol Sci. 2021 Mar 18;22(6):3116. doi: 10.3390/ijms22063116.
Cold atmospheric plasma (CAP) has attracted much attention in the fields of biotechnology and medicine owing to its potential utility in clinical applications. Recently accumulating evidence has demonstrated that CAP influences protein structures. However, there remain open questions regarding the molecular mechanisms behind the CAP-induced structural perturbations of biomacromolecules. Here, we investigated the potential effects of CAP irradiation of amyloid β (Aβ), an amyloidogenic protein associated with Alzheimer's disease. Using nuclear magnetic resonance spectroscopy, we observed gradual spectral changes in Aβ after a 10 s CAP pretreatment, which also suppressed its fibril formation, as revealed by thioflavin T assay. As per mass spectrometric analyses, these effects were attributed to selective oxidation of the methionine residue (Met) at position 35. Interestingly, this modification occurred when Aβ was dissolved into a pre-irradiated buffer, indicating that some reactive species oxidize the Met residue. Our results strongly suggest that the HO generated in the solution by CAP irradiation is responsible for Met oxidation, which inhibits Aβ amyloid formation. The findings of the present study provide fundamental insights into plasma biology, giving clues for developing novel applications of CAP.
冷等离体子体（CAP）因其在临床应用中的潜在应用而在生物技术和医学领域引起了广泛关注。最近积累的证据表明，CAP 会影响蛋白质结构。然而，关于 CAP 诱导生物大分子结构扰动的分子机制仍存在一些悬而未决的问题。在这里，我们研究了 CAP 辐照与阿尔茨海默病相关的淀粉样蛋白β（Aβ）的潜在影响。我们使用核磁共振波谱法观察到 Aβ在 10 秒 CAP 预处理后逐渐发生光谱变化，这也如噻唑黄素 T 测定法所揭示的那样抑制了其纤维形成。根据质谱分析，这些影响归因于甲硫氨酸残基（Met）位置 35 的选择性氧化。有趣的是，当 Aβ溶解在预先辐照的缓冲液中时，会发生这种修饰，表明一些反应性物质氧化了 Met 残基。我们的结果强烈表明，CAP 辐照在溶液中产生的 HO 负责 Met 氧化，从而抑制 Aβ 淀粉样形成。本研究的结果为等离子体生物学提供了基本的见解，为开发 CAP 的新应用提供了线索。
