Sub-angstrom conformational changes of a single molecule captured by AFM variance analysis.
Sub-angstrom conformational changes of a single molecule captured by AFM variance analysis.
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DOI：
10.1529/biophysj.105.076224
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发表时间：
2006-05
影响因子：
3.4
通讯作者：
Kirstin A. Walther;J. Brujic;Hongbin Li;Julio M. Fernandez
中科院分区：
文献类型：
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作者：
Kirstin A. Walther;J. Brujic;Hongbin Li;Julio M. Fernandez
可以分析系统的平衡方差，以更高的分辨率探测其潜在的动态。在这里，使用单分子原子力显微镜技术，我们展示了如何在一个单一的葡聚糖分子的长度的变化可以用来建立热力学平衡，并检测构象变化不能直接观察到与其他方法。葡聚糖由吡喃糖环链组成，每个吡喃糖环在拉伸力下经历从椅子到船构象的Angstrom尺度转变。我们的分子的波动方差分析验证了整个力延伸曲线的平衡，符合预期的热力学系综。这验证了对过渡区域中的方差的进一步分析，其揭示了在亚埃尺度上椅子和船之间的中间构象。我们的热平衡测试以及方差分析可以很容易地扩展到各种各样的分子，包括蛋白质。
A system's equilibrium variance can be analyzed to probe its underlying dynamics at higher resolution. Here, using single-molecule atomic-force microscope techniques, we show how the variance in the length of a single dextran molecule can be used to establish thermodynamic equilibrium and to detect conformational changes not directly observable with other methods. Dextran is comprised of a chain of pyranose rings that each undergoes an Angstrom-scale transition from a chair to boat conformation under a stretching force. Our analysis of the variance of the molecule's fluctuations verifies equilibrium throughout the force-extension curve, consistent with the expected thermodynamic ensemble. This validates further analysis of the variance in the transition region, which reveals an intermediate conformation between the chair and the boat on the sub-Angstrom scale. Our test of thermal equilibrium as well as our variance analysis can be readily extended to a wide variety of molecules, including proteins.