Force-clamp spectroscopy monitors the folding trajectory of a single protein
Force-clamp spectroscopy monitors the folding trajectory of a single protein
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DOI：
10.1126/science.1092497
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发表时间：
2004-03-12
期刊：
影响因子：
56.9
通讯作者：
Li, HB
中科院分区：
文献类型：
--
作者：
Fernandez, JM;Li, HB
我们用原子力显微镜测量了小分子蛋白泛素在单分子水平折叠过程中的末端长度。泛蛋白首先在大力下展开并延伸，然后终止拉伸力并观察蛋白质折叠。折叠轨迹是连续的，并分为几个不同的阶段。折叠所需的时间取决于未折叠蛋白质的轮廓长度和折叠过程中施加的拉伸力。折叠崩溃的标志是蛋白质的端到端长度的大波动，但这些波动消失后，最后折叠收缩。这些对蛋白质完整折叠轨迹的直接观察为确定折叠反应的物理基础提供了基准。
We used force-clamp atomic force micoscopy to measure the end-to-end length of the small protein ubiquitin during its folding reaction at the single-molecule level. Ubiquitin was first unfolded and extended at a high force, then the stretching force was quenched and protein folding was observed. The folding trajectories were continuous and marked by several distinct stages. The time taken to fold was dependent on the contour length of the unfolded protein and the stretching force applied during folding. The folding collapse was marked by large fluctuations in the end-to-end length of the protein, but these fluctuations vanished upon the final folding contraction. These direct observations of the complete folding trajectory of a protein provide a benchmark to determine the physical basis of the folding reaction.