Collaborative Research: Resolving How Excited-State Dynamics Couple into Long-Range Structural Changes in Native and Synthetic Light-Induced Photosensitive Proteins

有了这个奖项，生命过程化学项目将资助加州大学戴维斯分校的Delmar Larsen和俄克拉荷马州立大学的Wouter Hoff研究生物体如何捕获光并将其转化为生物活动。所有生物都使用蛋白质来调节它们对外部刺激的反应，但有些生物已经开发出对光敏感的特殊蛋白质。人体中的一个例子是位于眼睛中的蛋白质视紫红质，它吸收光线以获得视觉，并启动一系列信号事件，将光线中的信息传递给大脑。在这项研究中，一种被称为光活性黄色蛋白（PYP）的蛋白质正在被研究，因为它已经成为许多涉及蛋白质的光启动过程的一个被充分研究的模型。了解蛋白质活动的分子基础在根本上是很重要的。这对于开发新的工具也是必要的，通过这些工具，研究人员可以设计具有生物医学用途和工业用途的新功能的蛋白质，例如氢燃料产生或废物修复。这项工作对许多领域都有广泛的影响。研究人员正在为他们的在线图书馆ChemWiki开发新的模块，进一步扩大他们工作的影响。目前，每月有数百万学生在多所大学注册30多个课程。作为当前项目的一部分，研究人员正在构建UltraWiki和PhotoWiki，它们将为学生和公众传播有关光诱导生物过程的信息提供新的平台。光感受器蛋白是研究功能性蛋白反应活性的理想系统，因为它们是由短脉冲光触发的，并且它们的信号活动可以通过光谱技术直接跟踪。本项目着重于通过应用瞬态光谱方法研究新型PYP光感受器系统中光子转化为生物活性的光诱导反应机制。具体而言，该研究正在检查PYP类光传感器的光化学和构象变化。这些反应机制通过分子生物学方法的协同结合来表征，以产生新的光感受器系统和多脉冲超快光谱技术，这些技术能够在飞秒到毫秒的时间尺度上分辨瞬态电子、振动和结构动力学。电子动力学的研究，主要是通过泵-探针或泵-倾倒-探针的方法，被用来解决不均匀性，激发态和基态的演变，以及光产物形成动力学。这些信号与中红外探测和新颖的动态Förster共振能量转移（FRET）实验相补充，以提供对光激活后分子相互作用和光感受器系统配置的瞬态变化的结构洞察力。

With this award, the Chemistry of Life Processes Program is funding Delmar Larsen from University of California, Davis and Wouter Hoff from Oklahoma State University to study how light is captured by living organisms and converted into biological activity. All organisms use proteins to tune their response to external stimuli but some have developed specialized proteins that are sensitive to light. An example in the human body is the protein rhodopsin, located in the eye, that absorbs light for sight and initiates a cascade of signaling events that transmit the information in that light to the brain. In this research, a protein known as Photactive Yellow Protein, or PYP, is being investigated since it has become a well-studied model for many light-initiated process involving proteins. Understanding the molecular basis for the activity of proteins is important in a fundamental sense. It is also necessary for the development of new tools by which investigators might design proteins with new functions for both biomedical use and industrial use, such as hydrogen fuel generation or waste remediation. The work has a broad impact on a wide array of fields. The investigators are further broadening the impact of their work by developing new modules for their online library ChemWiki, which is currently being used by millions of students every month enrolled in over thirty courses at multiple universities. As part of the current project, the investigators are now constructing UltraWiki and PhotoWiki that will provide new platforms for disseminating information about light-induced biological processes to both students and the general public.Photoreceptor proteins are ideal systems to study functional protein reaction activity since they are triggered with short pulses of light, and their signaling activity may be directly followed via spectroscopic techniques. This project focuses on investigating the photoinduced reaction mechanisms underlying the conversion of photons into biological activity within novel PYP photoreceptor systems via the application of transient spectroscopic approaches. Specifically, the research is examining the photochemical and conformational changes in the PYP class of photosensors. These reaction mechanisms are being characterized through a synergistic combination of molecular biology approaches to generate novel photoreceptor systems and multipulse ultrafast spectroscopic techniques capable of resolving transient electronic, vibrational, and structural dynamics on a timescale of femtoseconds to milliseconds. Interrogation of the electronic dynamics, primarily via pump-probe or pump-dump-probe approaches, is being used to resolve inhomogeneity, excited-state and ground-state evolution, and photoproduct formation kinetics. These signals are complemented with mid-IR probing and novel dynamic Förster Resonant Energy Transfer (FRET) experiments to provide structural insight into the transient changes in molecular interactions and configuration of photoreceptors systems upon light activation.