Single-Molecule Stochastic Resonance
Single-Molecule Stochastic Resonance
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DOI：
10.1103/physrevx.2.031012
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发表时间：
2012-08-24
影响因子：
12.5
通讯作者：
Ritort, F.
中科院分区：
文献类型：
--
作者：
Hayashi, K.;de Lorenzo, S.;Ritort, F.
随机共振（SR）是动力系统中的一种常见现象。它由随机（随机或概率）噪声辅助的系统响应的放大和优化组成。在这里，我们进行了第一次实验研究SR在单一的DNA发夹表现出合作从折叠到未折叠的配置下的振荡的机械力的作用下的光镊的作用下的过渡。通过改变力振荡的频率，我们研究了在周期性驱动的自由能势场中DNA发夹结构的折叠和展开动力学。我们测量几个SR量词在不同条件下的实验装置，如陷阱刚度和长度的分子处理用于单分子操作。我们发现，一个很好的量化的SR是测量的DNA发夹的分子延伸的波动的谱密度的信噪比（SNR）。SNR的频率依赖性在由谐振匹配条件给出的频率值处呈现峰值。最后，我们进行了实验，显示如何SR可能是有用的，以提高低信噪比的构象分子转换的检测短发夹。
Stochastic resonance (SR) is a well-known phenomenon in dynamical systems. It consists of the amplification and optimization of the response of a system assisted by stochastic (randomor probabilistic) noise. Here we carry out the first experimental study of SR in single DNA hairpins which exhibit cooperatively transitions from folded to unfolded configurations under the action of an oscillating mechanical force applied with optical tweezers. By varying the frequency of the force oscillation, we investigate the folding and unfolding kinetics of DNA hairpins in a periodically driven bistable free-energy potential. We measure several SR quantifiers under varied conditions of the experimental setup such as trap stiffness and length of the molecular handles used for single-molecule manipulation. We find that a good quantifier of the SR is the signal-to-noise ratio (SNR) of the spectral density of measured fluctuations in molecular extension of the DNA hairpins. The frequency dependence of the SNR exhibits a peak at a frequency value given by the resonance-matching condition. Finally, we carry out experiments on short hairpins that show how SR might be useful for enhancing the detection of conformational molecular transitions of low SNR.