单分子位移映射表明小 (1 kDa) 溶液的不受阻碍的细胞内扩散
Alexander A Choi1, Limin Xiang1, Wan Li1
1Department of Chemistry, University of California, Berkeley, California 94720, United States.
Journal of the American Chemical Society
|April 7, 2023
概括
小分子的细胞内扩散速度比以前想象的要快,大部分细胞空间允许类似于水的运动. 大分子拥挤对这种扩散速度的影响很小.
科学领域:
- 细胞生物学
- 生物物理
- 分子动力学
背景情况:
- 小溶液 (1 kDa) 的细胞内扩散至关重要,但难以研究.
- 之前的方法难以标记和测量快速扩散系数 (> 300μm2/s).
研究的目的:
- 量化和空间绘制哺乳动物细胞内的小溶液的转化扩散.
- 克服测量高扩散系数和解决局部扩散变化的局限性.
主要方法:
- 使用超分辨率技术的单分子位移/扩散映射 (SMdM).
- 采用短距离为400μs的光照明脉冲.
- 将该方法应用于水溶性染料和染料标记的核酸.
主要成果:
- 已证明细胞内扩散在很大程度上不受阻碍,达到体外速率的60- 70% (高达~250μm2/ s).
- 确定了显著减缓扩散的亚微米区域,突出显示了空间分辨率的需要.
- 表明细胞溶液粘度具有适度的影响,而宏分子拥挤并不是主要障碍.
结论:
- 小溶液的细胞内扩散主要受到细胞质粘度的限制,而不是宏分子拥挤.
- 这项研究挑战了以前关于低细胞内扩散速度限制的假设.
- 空间解析的扩散映射对于理解细胞中的分子运输至关重要.
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