Study of damaging processes induced by direct core-excitations of DNA using electron spectroscopy

使用电子能谱研究 DNA 直接核心激发引起的损伤过程

基本信息

批准号：
18540326
负责人：
KAZUHIKO Mase
金额：
$ 2.46万
依托单位：
High Energy Accelerator Research Organization
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

Study of radiation-induced damaging processes of DNA is an important topic in radiation biology. The elucidation of the processes in atomic levels using electron spectroscopy, however, is a frontier field. The damaging processes are -roughly classified into two categories; one is the direct damaging processes induced by the electronic transitions of DNA itself; and the other is indirect processes induced by radicals formed by electric transitions of molecules surrounding DNA such as water. For the direct processes, the following three-step process, i. e., core-excitations, Auger processes, and ion desorption (Auger-stimulated ion desorption) is thought to play an important role. The aim of the present study is to investigate core-excitations, Auger processes, and ion desorption of DNA using X-ray photoelectron spectroscopy, ion kinetic energy measurements, and coincidence spectroscopy, and to clarify the processes of chemical bond breaking induced by direct core-excitations of DNA.We measured photoelectron photoion coincidence spectra and Auger-photoelectron coincidence spectra of DNA thiol self-assembled on gold surfaces. However most of the coincidence signals were smeared out by the accidental coincidence signals except for C-KVV-Auger-C-1s-photoelectron coincidence spectra. Since the signal/accidental ratio of the present coincidence spectrometer was found to be not sufficient enough, we have developed an improved apparatus for coincidence spectroscopy. We have improved an apparatus for the photoelectron spectroscopy at PF713L11D.

辐射引起的 DNA 损伤过程的研究是辐射生物学的一个重要课题。然而，使用电子光谱在原子水平上阐明这一过程是一个前沿领域。破坏过程大致分为两类：一是DNA本身的电子跃迁引起的直接破坏过程；另一种是由DNA周围分子（例如水）的电转变形成的自由基诱导的间接过程。对于直接过程，以下三步过程，i。例如，核心激发、俄歇过程和离子解吸（俄歇刺激离子解吸）被认为发挥着重要作用。本研究的目的是利用 X 射线光电子能谱、离子动能测量和符合光谱研究 DNA 的核心激发、俄歇过程和离子解吸，并阐明直接核心诱导的化学键断裂过程。 -DNA的激发。我们测量了在金表面自组装的DNA硫醇的光电子光离子符合光谱和俄歇光电子符合光谱。然而，除了C-KVV-Auger-C-1s-光电子符合谱外，大部分符合信号都被偶然符合信号抹掉了。由于发现现有符合光谱仪的信号/偶然比不够充分，我们开发了一种改进的符合光谱仪。我们改进了PF713L11D的光电子能谱装置。