THEORETICAL STUDIES ON THE DYNAMIC ASPECTS OF MACROMOLECULAR FUNCTION

在本报告所述期间，发表了关于下列项目的论文：(1)两态系统的单分子荧光光谱理论，(2)强碰撞模型相空间的首次通过时间，(3)Kramers类激活速率的周转过程。这里只简要介绍第一个项目。最近的技术进步使得使用包括单分子光谱学在内的各种技术来研究单分子在溶液中的行为成为可能。由于这类实验与在大系统上进行的实验不同，其结果会波动，因此需要新奇的理论来解释它们。在我们在这一新领域的第一项工作中，我们推导了在涉及单DNA和RNA分子的有限持续时间的实验中观察到的荧光衰减中指数幅度的概率分布的解析表达式。这一结果允许人们从这样的实验中提取构象变化的速率。由于整体实验只由不同构象的平衡布居决定，单分子实验，当适当分析时，会产生新的信息(例如构象变化的速率)。-单分子光谱学、荧光、速率过程

In this reporting period, papers dealing with the following projects appeared in print: (1) Theory of single molecule fluorescence spectroscopy of two state systems, (2) first passage time in phase space for the strong collision model, (3) Kramers like turnover of the rates of activation less processes. Only the first project will be briefly described here. Recent technological advances have made it possible to study the behavior of single molecules in solution using a variety of techniques including single molecule spectroscopy. Since such experiments, unlike those performed on bulk systems, lead to results that fluctuate, they require novel kinds of theories for their interpretation. In our first piece of work in this new area, we derived an analytic expression for the probability distribution of the amplitudes of the exponentials in the fluorescence decay observed in experiments of finite duration involving single DNA and RNA molecules. This result allows one to extract the rates of conformational changes from such experiments. Since bulk experiments are determined only by the equilibrium populations of the different conformers, single molecule experiments, when properly analyzed, lead to new kinds of information( e.g. the rates of conformational changes). - single molecule spectroscopy, fluorescence, rate processes