A Temperature-Jump Optical Trap for Single-Molecule Manipulation
A Temperature-Jump Optical Trap for Single-Molecule Manipulation
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DOI：
10.1016/j.bpj.2015.05.017
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发表时间：
2015-06-16
影响因子：
3.4
通讯作者：
Ritort, Felix
中科院分区：
文献类型：
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作者：
de Lorenzo, Sara;Ribezzi-Crivellari, Marco;Ritort, Felix
据我们所知，我们开发了一种新型的跳温光镊装置，可以局部快速改变温度。它使用的加热激光的波长可被水高度吸收，因此可以覆盖较宽的温度范围。该仪器可以记录单个分子在不同温度下的几条力-距离曲线，具有良好的热稳定性和机械稳定性。我们的设计具有减少对流和基线偏移的功能，这给以前的加热激光仪器带来了麻烦。为了证明准确性，我们使用该仪器进行了 DNA 解压缩实验，在实验中我们得出了 5 摄氏度至 50 摄氏度之间的温度范围内 DNA 双链体的平均碱基对自由能、熵和形成焓。我们还使用该仪器来表征单链 DNA (ssDNA) 的温度依赖性弹性，我们发现在低力和低温下存在显着的冷凝平台。奇怪的是，与简单的熵模型相反，在高压下测量的单链DNA的持久长度似乎随着温度的增加而增加。
To our knowledge, we have developed a novel temperature-jump optical tweezers setup that changes the temperature locally and rapidly. It uses a heating laser with a wavelength that is highly absorbed by water so it can cover a broad range of temperatures. This instrument can record several force-distance curves for one individual molecule at various temperatures with good thermal and mechanical stability. Our design has features to reduce convection and baseline shifts, which have troubled previous heating-laser instruments. As proof of accuracy, we used the instrument to carry out DNA unzipping experiments in which we derived the average basepair free energy, entropy, and enthalpy of formation of the DNA duplex in a range of temperatures between 5 degrees C and 50 degrees C. We also used the instrument to characterize the temperature-dependent elasticity of single-stranded DNA (ssDNA), where we find a significant condensation plateau at low force and low temperature. Oddly, the persistence length of ssDNA measured at high force seems to increase with temperature, contrary to simple entropic models.