Transient Intermediates in Electron and Proton Transfer

电子和质子转移中的瞬态中间体

• 批准号: 0750048
• 负责人: Frantisek Turecek
• 金额: $ 40.62万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0750048&HistoricalAwards=false
• 关键词: Transient; Intermediates; Electron; Proton; Transfer

With the support of an award from the Organic and Macromolecular Chemistry Program, Professor Franticek Turecek will address highly reactive molecules, radicals, and cation-radical intermediates that are produced by electron transfer to and deprotonation of cations derived from polar molecules such as peptides, nucleosides, and transition metal complexes. The knowledge gained from the proposed studies will be used to explain the reactivity of transient species relevant to electron-ion and ion-ion recombination processes in biomolecules of current interest and to formulate specific and general mechanisms governing the stability and unimolecular dissociations of a variety of highly reactive and elusive species. The proposed studies of reactive intermediates will employ experimental methods allowing for femtosecond collisional electron transfer in beam experiments, as well as electron capture in isolated ions trapped in electrostatic and magnetic fields. Special model compounds will be synthesized to separate intramolecular interactions by restricting the peptide ion conformational space. Fixed-charge groups will be used to control the energetics of electron attachment and transfer and thus to affect the electronic state(s) that are accessed by ion-electron recombination and collisional electron transfer. Ab initio computational methods will be employed to provide relative, dissociation, and transition state energies to be used for RRKM calculations of unimolecular dissociation and isomerization rate constants. Intellectual meritThe proposed research addresses fundamental and hitherto unresolved questions regarding the dissociations of peptide radicals and cation-radicals. Experiments are proposed that will permit the study of unimolecular dissociations of these transient species on a range of short time scales and under conditions of electron attachment and femtosecond collisional transfer. Electron structure theory calculations are an integral part of the proposed research in both experiment planning and data interpretation.Broader impactsPeptide radicals and cation-radicals have been of considerable interest due to their role as intermediates in mass spectrometric analytical methods for peptide sequencing and detection of protein post-translational modifications. Applications of these methods extend to biology, medicine, and other life sciences, and have been fueled by the availability of commercial instruments for electron capture dissociation and electron transfer dissociation. However, fundamental understanding of the chemistry of transient peptide cation-radicals is essential for the rational use of electron-based methods for peptide and protein sequencing. Studies of ion discharge and immobilization on metal-oxide surfaces have already brought practical results in procedures for the manufacturing of special surfaces for medical implants and selective mass spectrometric detection of phosphopeptides. The proposed research in this area is aimed at gaining insight into the processes leading to biomolecule discharge and immobilization on surfaces.

在有机和大​​分子化学计划的奖励的支持下，Franticek Turecek教授将解决通过电子转移到阳离子和从极性分子（例如肽，肽，核化金属复合物）和过度分子的阳离子产生的高反应性分子，自由基和阳离子激进的中间体。从提出的研究中获得的知识将用于解释当前感兴趣的生物分子中与电子离子和离子离子重组过程相关的短暂物种的反应性，并制定了管理多种高度反应性和难以捉摸的物种的稳定性和非分子分离的特定和一般机制。提议的反应性中间体的研究将采用实验方法，允许在光束实验中进行飞秒犯罪的电子转移，以及被困在静电和磁场中的分离离子中的电子捕获。 特殊模型化合物将通过限制肽离子构象空间而合成以分离分子内相互作用。固定电荷组将用于控制电子附着和转移的能量，从而影响通过离子电子重组和碰撞电子传递访问的电子状态。从头算计算方法将用于提供相对，分离和过渡状态能量，用于用于单分子解离和异构化速率常数的RRKM计算。 知识分子优点拟议的研究涉及有关肽自由基和阳离子 - 自由基解离的基本和迄今未解决的问题。提出了实验，该实验将允许研究这些瞬态物种的单分子解离，并在一系列短的时间尺度和在电子附着和飞秒碰撞转移的条件下进行研究。电子结构理论计算是实验规划和数据解释中提出的研究的组成部分。BroaderImpact肽自由基和阳离子 - 自由基因其在质谱分析方法中作为肽测序和检测蛋白质后传递后修饰的质谱分析方法的作用而引起了极大的兴趣。这些方法的应用扩展到生物学，医学和其他生命科学，并因电子捕获捕获分离和电子传递分离的可用性而助长了。然而，对瞬时肽阳离子 - 自由基化学的基本了解对于合理使用基于电子的肽和蛋白质测序的方法至关重要。对金属氧化物表面的离子排放和固定化的研究已经为制造特殊植入物的特殊表面和选择性质谱检测磷酸肽的方法带来了实际结果。该领域的拟议研究旨在了解导致生物分子排放和固定在表面上的过程。