Ultra-stable, high-bandwidth measurement platform for high-precision studies of rapid conformational dynamics in single biomolecules

像蛋白质、DNA和RNA这样的生物分子形成了它们正常运作所需的复杂结构。了解这些结构如何形成（称为“折叠”）对于理解正常功能和功能障碍（可能导致疾病）都很重要。研究折叠最灵敏的方法之一是使用激光镊子抓住单个分子，并通过拉开它们来解开它们的结构。这个提议将建立一个超稳定的系统来测量单分子的折叠，一个可以在很长一段时间（几十分钟）内以原子尺度分辨率观察非常快（~1 μs）的事件的系统，提供迄今为止这些分子实时结构变化的最精确测量。我们将用它来研究一些基本问题，比如折叠作为一个物理过程是如何工作的，是什么决定了观察到的特定行为。更具体地说，我们将研究折叠过程中寿命最短的事件，即难以捉摸的“过渡状态”，它在折叠过程中充当瓶颈，因此主导了动力学。经过过渡态的路径包含了折叠机制的所有关键信息，但很难检测到。我们将测量这些“过渡路径”，不仅是为了了解折叠的基本物理原理，也是为了了解折叠是如何出问题的：这种错误折叠是许多不治之症的根源，如阿尔茨海默氏症和ALS，但在分子水平上驱动它的机制仍然知之甚少。此外，我们将使用新仪器来研究仍未解决的生物过程，如病毒如何改变遗传密码的读取方式，这构成了重要的科学谜题，但也有潜在的医学应用。像这样的研究，利用单分子探针令人难以置信的分辨率和灵敏度，是折叠研究中最热门的前沿之一。我们现在有一个非凡的机会，可以在一个与生物、物理、化学和医学相关的几十年的问题上取得重大而持久的进展。如果没有这些仪器，我们将无法从事如此激动人心的科学研究。

Biological molecules like proteins, DNA, and RNA form complex structures that are required for them to function correctly. Understanding how these structures form (known as ‘folding’) is important for understanding both proper function and dysfunction (which may lead to disease). One of the most sensitive ways to study folding is to use laser tweezers to grab onto single molecules and unravel their structure by pulling them apart. This proposal will build an ultra-stable system for measuring the folding of single molecules, one that can observe very rapid (~1 μs) events with atomic-scale resolution over long periods of time (tens of minutes), providing the most precise measurements to date of real-time structural changes in these molecules. We will use it to study fundamental questions such as how folding works as a physical process and what determines the specific behaviour observed. More specifically, we will study the very shortest-lived events during folding, the elusive ‘transition states’ that act as bottlenecks in the process and therefore dominate the dynamics. The path taken through the transition states contains all the critical information about the mechanism of folding, but it is very hard to detect. We will measure these ‘transition paths’ not only to learn about the basic physical principles of folding, but also to understand how folding goes wrong: such misfolding is at the root of many incurable diseases, like Alzheimer’s and ALS, but the mechanisms that drive it at the molecular level remain poorly understood. Furthermore, we will use the new instrument to study still-unsolved biological processes like how viruses can alter the way the genetic code is read, which pose important scientific riddles but also have potential applications in medicine. Studies like these, making use of the incredible resolution and sensitivity of single-molecule probes, are one of the hottest frontiers in folding studies. We have right now a remarkable opportunity to make significant and lasting advances in a decades-old problem with relevance to biology, physics, chemistry, and medicine. Without this instrumentation, we will not be able to pursue such exciting science.