Conformational dynamics in peptides and proteins on the nanoseconds to microseconds time scale

蛋白质在不同的构象状态之间处于平衡状态。这些状态之间的转换与它们的生物学功能密切相关。在这个项目中，我们的目标是在纳秒到微秒的时间尺度上研究肽和蛋白质的构象动力学。在这个时间尺度上的动力学是实验上难以表征的，因此人们对其了解甚少。我们将使用实验生物物理方法来研究多肽和蛋白质的构象平衡，以确定它们的结构，热力学和动力学性质。在我们提出的实验中，我们将把快速三重态-三重态能量转移（TTET）与构象平衡结合起来，以获得纳秒到微秒时间尺度上的平衡波动信息。这种方法对局部和全局展开反应都很敏感，并且能够区分不同的构象亚态，即使它们在结构上非常相似。实验将得到平衡的热力学和动力学信息。此外，我们将进行氢/氘（H/D）交换和高压核磁共振实验，这些实验将提供不同构象态的详细结构信息。我们将研究α -螺旋和β -发夹肽的动力学，以及肌动蛋白结合绒毛蛋白头饰结构域（HP35， HP45和HP67）的不同变体。与此同时，庄丽莲教授的研究小组将研究具有显式水的分子动力学（MD）模拟的相同模型系统。我们的实验研究结果与全原子MD模拟相结合，将给出蛋白质和多肽构象波动的详细结构和动态图像。

Proteins exist in an equilibrium between different conformational states. The transitions between these states are closely connected to their biological function. In this project we aim to investigate conformational dynamics in peptides and proteins on the nanoseconds to microseconds time scale. Dynamics on this time scale are experimentally difficult to characterize and are thus only poorly understood. We will use experimental biophysical methods to study conformational equilibria in peptides and proteins in order to determine their structural, thermodynamic and dynamic properties. In the proposed experiments we will couple fast triplet-triplet-energy-transfer (TTET) to conformational equilibria to obtain information on equilibrium fluctuations on the nanoseconds to microseconds time scale. This method is sensitive for local and global unfolding reactions and is able to discriminate between different conformational substates, even when they are structurally very similar. The experiments will yield both thermodynamic and dynamic information on the equilibria. In addition, we will conduct hydrogen/deuterium (H/D) exchange and high-pressure NMR experiments, which will give detailed structural information on the different conformational states. We will study the dynamics of alpha-helical und beta-hairpin peptides as well as different variants of the actin-binding villin headpiece domain (HP35, HP45 and HP67). In parallel, the group of Prof. Lillian Chong will study the same model systems with molecular dynamics (MD) simulations with explicit water. The combination of results from our experimental studies and the all-atom MD simulations will give a detailed structural and dynamic picture of conformational fluctuations in proteins and peptides.