Bayesian estimates of free energies from nonequilibrium work data in the presence of instrument noise
Bayesian estimates of free energies from nonequilibrium work data in the presence of instrument noise
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DOI：
10.1063/1.2937892
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发表时间：
2008-07-14
影响因子：
4.4
通讯作者：
Crooks, Gavin E.
中科院分区：
文献类型：
--
作者：
Maragakis, Paul;Ritort, Felix;Crooks, Gavin E.
Jarzynski等式和涨落定理将平衡自由能差与功的非平衡测量联系起来。这些关系延伸到单分子实验中，这些实验探测了蛋白质和核酸的有限时间热力学。以前没有考虑实验误差和仪器噪声的影响。在这里，我们提出了一种贝叶斯形式来估计非平衡功测量的自由能变化，该形式补偿了仪器噪声并结合了来自多种驱动协议的数据。我们重新分析了最近的一组实验，在这些实验中，单个RNA发夹用光学镊子以三种不同的速率展开和折叠。有趣的是，最快和离平衡最远的测量包含最小的仪器噪声，因此，比一些慢的、更嘈杂的、接近平衡的测量提供更准确的自由能估计。我们在这里提出的方法将扩展单分子实验的范围；它们可用于原子力显微镜、光学镊子和磁镊子测量数据的分析。(c) 2008年美国物理研究所。
The Jarzynski equality and the fluctuation theorem relate equilibrium free energy differences to nonequilibrium measurements of the work. These relations extend to single-molecule experiments that have probed the finite-time thermodynamics of proteins and nucleic acids. The effects of experimental error and instrument noise have not been considered previously. Here, we present a Bayesian formalism for estimating free energy changes from nonequilibrium work measurements that compensates for instrument noise and combines data from multiple driving protocols. We reanalyze a recent set of experiments in which a single RNA hairpin is unfolded and refolded using optical tweezers at three different rates. Interestingly, the fastest and farthest-from-equilibrium measurements contain the least instrumental noise and, therefore, provide a more accurate estimate of the free energies than a few slow, more noisy, near-equilibrium measurements. The methods we propose here will extend the scope of single-molecule experiments; they can be used in the analysis of data from measurements with atomic force microscopy, optical, and magnetic tweezers. (c) 2008 American Institute of Physics.