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合理应用和开发新的理论方法来解释它们，以便尽可能地提取微观信息。在本报告所述期间，发表了四篇论文，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实验室的椭圆电子实验结果进行了比较(2)发展了单分子光谱学中光子计数的一般理论(特别是任意动力学方案中跃迁的统计)，并将其应用于哈佛大学谢孙尼实验室的单分子酶催化实验的分析。(3)发展了一种新的理论来提取单分子拉伸实验中的动力学信息(特别是本征活化速率和自由能)，该实验使用了光钳和原子力显微镜。这是对去年报道的从单分子力谱获得平衡自由能表面的工作的补充(4)首次提出了激光光束内外扩散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的性质的信息。这些论文中的最后三篇代表了我们在解释单分子作用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.