Following molecular structure and dynamics in real time using femtosecond stimulated Raman spectroscopy

使用飞秒受激拉曼光谱实时跟踪分子结构和动力学

• 批准号: EP/H003541/1
• 负责人: Philipp Kukura
• 金额: $ 177.44万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2010
• 资助国家: 英国
• 起止时间: 2010 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FH003541%2F1
• 关键词: Following; molecular; structure; dynamics; real

To understand function, study structure . Francis Crick made this statement after his elucidation of the structure of DNA revolutionized not only the scientific community but also society as a whole. While it was made with the microscopic world in mind, it is equally true in our day-to-day macroscopic world. If we were presented with a car engine and asked to investigate how it functions we would probably do two things: Firstly, we take it apart to find out what it consists of, how it is constructed and which parts are moving. Secondly, we might change the fuel, play with the electronics and connect and disconnect any cables we may find to gain insight into which parts are essential and what their function is. In many ways, proteins, the work horses of our body, are a microscopic equivalent of that car engine, except that they usually are much more complex and more importantly, much more efficient at what they do. To understand their function, we use the same approach outlined above. We try to learn as much as possible about their structure using various spectroscopic techniques and change various parts of the protein, its environment and fuel to determine how it works. The only thing we usually cannot do is to watch them do their work in real time. How important this is, is best demonstrated by the inner workings of a watch. Looking inside a dead watch makes it difficult to understand how it works, but watching all the parts move makes it much easier. These concepts are equally true for protein function as for the structural changes associated with chemistry in general.The fundamental problem in observing how atoms rearrange during a (bio)chemical process is that they move incredibly fast, usually on the time scale of femtoseconds. (To put this in perspective: one femtosecond compares to five minutes as five minutes to the existence of the universe.) It is thus necessary to create a camera to capture structural snapshots of the reacting species as the chemical change proceeds. Molecules consist of atoms that are held together by electronic bonds. The motions of these atoms are usually described by molecular vibrations. Since the strength of these bonds is closely connected to the three-dimensional structure of the molecule, it is possible to follow any changes in structure by recording the energy of molecular vibrations as a function of time. Traditionally, such techniques have been orders of magnitude too slow to directly observe molecular change. To achieve this goal I would like to establish novel spectroscopic techniques based on vibrational spectroscopy using femtosecond laser pulses that enable the observation of molecular structure in real time. These techniques will be based on recent results suggesting that the limits established by the uncertainty principle can be circumvented to achieve the necessary temporal and energy sensitivity.This ability should enable me to address many fundamental questions in the, biologically relevant, condensed phase such as: how is energy redistributed throughout a molecule? what is the role of the solvent in guiding a photochemical process? how are enzyme-substrate complexes formed and what are their structural and temporal dynamics? In analogy with the above comparison: I hope to visualize the moving pistons of biochemical and chemical reactions.

要理解功能，就要研究结构。弗朗西斯·克里克在阐明DNA的结构后发表了这一声明，他不仅彻底改变了科学界，也彻底改变了整个社会。虽然它是从微观世界出发的，但在我们日常的宏观世界中也是如此。如果向我们展示一台汽车发动机，并要求我们调查它是如何工作的，我们可能会做两件事：首先，我们拆开它，找出它是由什么组成的，它是如何构造的，以及哪些部件在移动。其次，我们可能会更换燃料，摆弄电子设备，连接和断开我们可能找到的任何电缆，以了解哪些部件是必不可少的，它们的功能是什么。在许多方面，蛋白质，我们身体的工作马匹，就像是汽车引擎的微观等价物，除了它们通常要复杂得多，更重要的是，它们的工作效率要高得多。为了理解它们的功能，我们使用上面概述的相同方法。我们试图使用各种光谱技术尽可能多地了解它们的结构，并改变蛋白质的不同部分，它的环境和燃料，以确定它是如何工作的。我们通常不能做的唯一一件事就是实时观看他们的工作。这一点有多重要，通过手表的内部工作原理得到了最好的证明。看一块死表的内部，很难理解它是如何工作的，但观察所有部件的运动会容易得多。这些概念同样适用于蛋白质功能，也适用于与化学有关的结构变化。观察原子在(生物)化学过程中如何重排的基本问题是，它们移动得令人难以置信地快，通常是在飞秒的时间尺度上。(客观地说：一飞秒相当于五分钟，相当于宇宙存在的五分钟。)因此，有必要创建一台照相机，在化学变化进行时捕捉反应物种的结构快照。分子由原子组成，原子通过电子键结合在一起。这些原子的运动通常用分子振动来描述。由于这些键的强度与分子的三维结构密切相关，因此可以通过记录分子振动的能量作为时间的函数来跟踪结构的任何变化。传统上，这样的技术速度太慢，无法直接观察分子变化。为了实现这一目标，我想建立基于使用飞秒激光脉冲的振动光谱学的新的光谱技术，从而能够实时观察分子结构。这些技术将基于最近的结果，这些结果表明，可以绕过不确定性原理建立的限制，以实现必要的时间和能量敏感性。这种能力应该使我能够在生物相关的凝聚阶段解决许多基本问题，例如：能量如何在整个分子中重新分配？溶剂在指导光化学过程中的作用是什么？酶-底物复合体是如何形成的？它们的结构和时间动力学是什么？与上面的比较类比：我希望能想象生化反应和化学反应的运动活塞。

项目成果

Direct Observation of the Coherent Nuclear Response after the Absorption of a Photon

• DOI: 10.1103/physrevlett.112.238301
• 发表时间: 2014-06-09
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Liebel, M.;Schnedermann, C.;Kukura, P.
• 通讯作者: Kukura, P.

Two-Dimensional Impulsively Stimulated Resonant Raman Spectroscopy of Molecular Excited States

• DOI: 10.1103/physrevx.10.011051
• 发表时间: 2020-02-28
• 期刊: PHYSICAL REVIEW X
• 影响因子: 12.5
• 作者: Fumero, Giuseppe;Schnedermann, Christoph;Scopigno, Tullio
• 通讯作者: Scopigno, Tullio

Non-Hermitian dynamics in the quantum Zeno limit

• DOI: 10.1103/physreva.94.012123
• 发表时间: 2015-10
• 期刊: Physical Review A
• 影响因子: 2.9
• 作者: W. Kozlowski;S. Caballero-Benitez;I. Mekhov