PUMP-PROBE SPECTROSCOPY OF PROTON-COUPLED ELECTRON TRANSFER IN PROTEINS

蛋白质中质子耦合电子转移的泵探针光谱

• 批准号: 7598439
• 负责人: MICHAEL J THERIEN
• 金额: $ 1.19万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7598439
• 关键词: Arts; Binding; Biological; Biology; Charge; Computer Retrieval of Information on Scientific Projects Database; Coupled; Data; Electron Transport; Electrostatics; Event; Funding; Goals; Grant; Institution; Investigation; Link; Mediating; Methodology; Methods; Molecular; Nature; Nuclear; Object Attachment; Optics; Peptides; Pigments; Process; Protein Engineering; Proteins; Protons; Pump; Reaction; Research; Research Personnel; Research Project Grants; Resources; Source; Spectrum Analysis; Structure-Activity Relationship; System; Time; United States National Institutes of Health; Work; bond fast; chromophore; cofactor; design; desire; insight; instrumentation; migration; nanosecond; research study; response; vibration

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The primary goal of this research project is to exploit the unique information that ultrafast vibrational spectroscopy provides to develop fundamental insights into ultrafast processes relevant to biology. We thereby intend to (1) identify key vibrational signatures of intermediate states involved in electron transfer, (2) ascertain the extent to which charge migrates in strongly coupled donor-acceptor systems, (3) examine the dynamics of reactions such as ultrafast proton-coupled electron transfer in which fast bond-breaking and bond-forming events occur on time scales similar to charge migration, (4) understand the nature of excited-state chromophore nuclear dynamics, and (5) probe the nature of electronically excited states in delocalized, multi-pigment systems. The types of dynamics-correlated ET experiments that we intend to pursue will utilize state-of-the-art experimental methodologies and instrumentation to study molecular vibrations on fast, sub-nanosecond time scales. Optical pump-probe, optical-pump/infrared-probe and dynamics Stokes shift experiments will be correlated with experiments such as transient optical pump-probe experiments. This work will delineate structure-function relationships important to protein-mediated, proton-coupled electron-transfer (PCET) reactions. These investigations will rely on the design of de novo tetra-alpha-helical proteins engineered to bind donor - spacer - acceptor (D-Sp-A) supermolecules and covalently linked multi-cofactor assemblies. While these systems possess reduced structural complexity with respect to biological proteins, in the sense that they exploit mainly helical bundle motifs, they enable independent modulation of the local electrostatic forces that surround D, A, and chromophore; furthermore, design features of these tetra-alpha-helical proteins allow control over the nature of cofactor first- and second-sphere H-bonding interactions. We will examine photoinduced PCET reactions in such systems using optical pump / optical probe and visible pump / IR probe spectroscopic methods, and correlate the observed dynamics with specific responses of the peptide matrix. Such data provide key information that will enable us to fully exploit powerful computational approaches to elaborate protein design to effect desired function.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目及 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 该研究项目的主要目标是利用超快振动光谱提供的独特信息来深入了解与生物学相关的超快过程。因此，我们打算（1）识别电子转移中涉及的中间态的关键振动特征，（2）确定强耦合供体-受体系统中电荷迁移的程度，（3）检查超快质子反应等反应的动力学。耦合电子转移，其中快速断键和成键事件在类似于电荷迁移的时间尺度上发生，（4）了解激发态发色团核动力学的本质，以及（5）探测电子激发态的本质离域的多颜料系统。 我们打算进行的与动力学相关的 ET 实验类型将利用最先进的实验方法和仪器来研究快速、亚纳秒时间尺度的分子振动。光泵浦探针、光泵/红外探针和动态斯托克斯位移实验将与瞬态光泵浦探针实验等实验相关联。 这项工作将描绘对蛋白质介导的质子耦合电子转移（PCET）反应重要的结构-功能关系。 这些研究将依赖于从头设计四α螺旋蛋白，该蛋白被设计用于结合供体-间隔子-受体（D-Sp-A）超分子和共价连接的多辅因子组件。 虽然这些系统相对于生物蛋白质具有降低的结构复杂性，但从它们主要利用螺旋束基序的意义上来说，它们能够独立调节 D、A 和发色团周围的局部静电力；此外，这些四α螺旋蛋白的设计特征允许控制辅因子第一球和第二球氢键相互作用的性质。 我们将使用光泵/光学探针和可见光泵/红外探针光谱方法检查此类系统中的光诱导 PCET 反应，并将观察到的动力学与肽基质的特定响应相关联。 这些数据提供了关键信息，使我们能够充分利用强大的计算方法来精心设计蛋白质，以实现所需的功能。