Ultrafast chemical biology in the gas phase

气相超快化学生物学

• 批准号: EP/D054508/1
• 负责人: Helen Fielding
• 金额: $ 33.24万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD054508%2F1
• 关键词: Ultrafast; chemical; biology; gas; phase

Since the elucidation of the entire human genetic sequence, scientists have been inundated with a wealth of information on protein structure. However, although the availability of a protein structure is valuable, it may not provide any information on the biological function of a specific protein. In photoinduced biomolecular processes, the protein environment of the chromophore plays an essential role in determining the reaction pathway and product distribution of the chromphore. Whilst in solution based reactions the chromophore molecules move freely around within the solvent, in protein based reactions the protein environment provides both a static and dynamical constraint on the motions of the constituent atoms within the chromophore. In order to understand the role of the protein environment on photoinduced biological processes in detail it is necessary to investigate the dynamics of the chromophore in a controlled environment, i.e. in the gas-phase. One of the experimental challenges is generating a stable source of the chromophore in its controlled protein environment. Electrospray ionisation (ESI) has emerged as a very powerful soft ionisation method that has the capability of taking any molecule that exists in solution into the gas phase in its native environment or a well-controlled artificial environment, including proteins as large a several hundred kilodaltons. The dynamics take place on the timescale of nuclear rearrangement, i.e. the femtosecond timescale (1 femtosecond = 1 millionth of a billionth of a second). Therefore, femtosecond laser sources are ideal tools for observing the dynamics of these biological processes in real time. But the value of any time-resolved femtosecond experiment depends on the probe scheme and the challenge is to find a global detection method. Time-resolved photoelectron imaging spectroscopy has recently emerged as an extremely powerful technique for mapping out ultrafast dynamical processes in the gas phase. An initial pump laser pulse excites an electron in the chromophore and a delayed probe laser pulse ionises the molecule. The kinetic energies of the photoelectrons and their angular distributions provide information about the geometry of the chromophore and its electronic wave function at the time of ionisation. Ionisation is a global phenomenon so with this approach there is, in principle, no limitation to the type of system that that can be investigated. We propose to design, construct and optimise a unique instrument comprising an electrospray or nanospray source, a time-of-flight mass spectrometer and photoelectron imaging apparatus for investigating the ultrafast dynamics of real biological systems of several hundreds of kDa. To test the instrument we will investigate the dynamics of the model biological system Bacteriorhodopsin - the molecule responsible for light detection in the process of vision. Although the science will be interesting in its own right as there is still some controversy over the photochemical pathway, the most successful outcome of this project will be to demonstrate the potential of this new instrument as a generic tool for studying fundamental biological processes. In the longer term we would hope to explore the possibilities of using this type of approach to study transient protein-protein interactions, protein-ligand interactions and fundamental protein folding mechanisms. We would then be in a strong position to explore the possibility of mutating the protein environment or shaping the femtosecond light pulses to enable us to identify patterns of dynamic behaviour unique to specific biological systems.

自从整个人类基因序列被阐明以来，科学家们被大量关于蛋白质结构的信息所淹没。然而，尽管蛋白质结构的可用性是有价值的，但它可能无法提供有关特定蛋白质生物功能的任何信息。在光诱导的生物分子过程中，生色团的蛋白质环境在决定生色团的反应途径和产物分布方面起着至关重要的作用。虽然在基于溶液的反应中，发色团分子在溶剂内自由移动，但在基于蛋白质的反应中，蛋白质环境对发色团内组成原子的运动提供了静态和动态约束。为了详细了解蛋白质环境对光诱导的生物过程的作用，有必要研究发色团在受控环境中，即在气相中的动力学。实验挑战之一是在其受控的蛋白质环境中产生稳定的发色团来源。电喷雾电离（ESI）已经成为一种非常强大的软电离方法，其具有将溶液中存在的任何分子在其天然环境或良好控制的人工环境中带入气相的能力，包括大到几百千道尔顿的蛋白质。动力学发生在核重排的时间尺度上，即飞秒时间尺度（1飞秒=十亿分之一秒的百万分之一）。因此，飞秒激光源是真实的时间观察这些生物过程的动力学的理想工具。但是任何时间分辨飞秒实验的价值都取决于探测方案，挑战在于找到一种全局探测方法。时间分辨光电子成像光谱技术是近年来发展起来的一种非常强大的技术，用于绘制气相中的超快动力学过程。初始泵浦激光脉冲激发发色团中的电子，延迟的探测激光脉冲使分子电离。光电子的动能和它们的角分布提供了关于发色团的几何形状及其在电离时的电子波函数的信息。电离是一种全球现象，因此原则上，使用这种方法对可以研究的系统类型没有限制。我们建议设计，构建和优化一个独特的仪器，包括电喷雾或纳米喷雾源，飞行时间质谱仪和光电子成像装置，用于研究数百kDa的真实的生物系统的超快动力学。为了测试仪器，我们将研究模型生物系统细菌视紫红质的动力学-负责视觉过程中光检测的分子。虽然科学本身将是有趣的，因为在光化学途径上仍然存在一些争议，但该项目最成功的成果将是展示这种新仪器作为研究基本生物过程的通用工具的潜力。从长远来看，我们希望探索使用这种方法来研究瞬时蛋白质-蛋白质相互作用，蛋白质-配体相互作用和基本蛋白质折叠机制的可能性。然后，我们将处于有利地位，探索突变蛋白质环境或塑造飞秒光脉冲的可能性，使我们能够识别特定生物系统特有的动态行为模式。

项目成果

Controlling electron emission from the photoactive yellow protein chromophore by substitution at the coumaric acid group.

通过香豆酸基团的取代来控制光活性黄色蛋白发色团的电子发射。

• DOI: 10.1039/c6cp00565a
• 发表时间: 2016
• 期刊: PCCP
• 作者: Parkes MA

Mechanism of resonant electron emission from the deprotonated GFP chromophore and its biomimetics.

• DOI: 10.1039/c6sc05529j
• 发表时间: 2017-04-01
• 期刊: Chemical science
• 影响因子: 8.4
• 作者: Bochenkova AV;Mooney CRS;Parkes MA;Woodhouse JL;Zhang L;Lewin R;Ward JM;Hailes HC;Andersen LH;Fielding HH
• 通讯作者: Fielding HH

Controlling Radical Formation in the Photoactive Yellow Protein Chromophore

控制光活性黄色蛋白发色团中自由基的形成

• DOI: 10.1002/ange.201500549
• 发表时间: 2015
• 期刊: Angewandte Chemie
• 作者: Mooney C

Photodetachment spectra of deprotonated fluorescent protein chromophore anions.

去质子化荧光蛋白发色团阴离子的光脱离光谱。

• DOI: 10.1021/jp3058349
• 发表时间: 2012
• 期刊: The journal of physical chemistry. A
• 作者: Mooney CR

Development of a new photoelectron spectroscopy instrument combining an electrospray ion source and photoelectron imaging.

开发结合电喷雾离子源和光电子成像的新型光电子能谱仪器。

• DOI: 10.1063/1.3505097
• 发表时间: 2010
• 期刊: The Review of scientific instruments
• 作者: McKay AR