Theoretical Studies On The Dynamic Aspects Of Macromolec

在过去的几年里，我们在研究单个大分子的行为方面取得了巨大的进步。这些新的实验需要尖端技术的复杂应用和新的理论方法的发展来解释它们，以便提取最大可能的微观信息。这已成为我们最近研究的主要焦点。在本报告期间，有四篇论文涉及以下主题：(1)超微电极电流分析理论的发展。将该理论的预测结果与北卡罗来纳大学Mark Wightman实验室用椭圆电极得到的实验结果进行了比较。(2)发展了单分子光谱光子计数的一般理论（特别是任意动力学方案中的跃迁统计），并将其应用于哈佛大学Sunney Xie实验室进行的单分子酶催化实验的分析。(3)提出了一种利用光学镊子和原子力显微镜从单分子拉扯实验中提取动力学信息（特别是本征速率和激活自由能）的新理论。这补充了去年报道的从单分子力谱中获得平衡自由能面协议的工作。(4)首次提出了扩散进出激光束的分子的光子计数直方图理论。这种直方图包含有关荧光团构象变化性质的信息。这些论文中的最后三篇代表了我们在解释单分子力和荧光光谱实验方面的重大进步。

Dramatic advances have been made in the last few years in our ability to study the behavior of single macromolecules. These new experiments require sopisticated applications of cutting-edge technologies and the development of new theoretical approaches to interpret them so as to extract the maximum possible microscopic information. This has recently become the main focus of our research.In this reporting period, four papers papers dealing with the following topics appeared in print: (1) The development of an analytic theory for the current at ultramicroelectrodes. The predictions of this theory were compared with experimental results obtained using elliptical electordes obtained in the laboratory of Mark Wightman at the University of North Carolina (2) The general theory of photon counting in single-molecule spectroscopy ( specifically the statistics of transitions in an arbitratry kinetic scheme) was developped and applied to the the analysis of experiments on single molecule enzyme catalysis perfomed in the laborastory of Sunney Xie at Harvard. (3) A novel theory was developped to extract kinetic information ( specifically the intrinsic rates and free energies of activation) from single molecule pulling experiments performed using optical tweezers and atomic force microscopes. This complements the work reported last year dealing with the protocal of obtaining equilibrium free energy surfaces from single molecule force spectroscopy (4) The theory of photon counting histograms for molecules that diffuse in and out of the laser beam was formulated for the first time . Such histograms contain information about the nature of conformational changes of the fluorophores. The last three of these papers represent a significant advance in our ability to interpret single-molecule force and fluorescence spectroscopic experiments.