Mechanisms of direct and indirect DNA damages induced by stimuli from environment such as radiation and active oxygen

辐射、活性氧等环境刺激引起的直接和间接DNA损伤机制

基本信息

批准号：
16205003
负责人：
AIDA Misako
金额：
$ 31.95万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16205003/
关键词：
nucleic acid bases keto-enol tautomers amino-imino tautomers soft X-ray radiation inner-shell ionization low temperature argon matrix ab initio molecular orbital method QM MM hybrid method 赤外分光法量子化学 DNA塩基アミノ基水素結合ラジカル光反応

项目摘要

To investigate the mechanisms of direct damage to DNA bases induced by radiation, we studied the fragmentation of a model molecule, 2-amino-3methylpyridine, at the carbon and nitrogen K-edges. We found that at the nitrogen K-shell ionization energies a specific reaction occurs in which fragment ions with the breakup around the nitrogen atoms are significantly produced. The proposed fragmentation mechanism for this system is supported by the experiments with 2-, 3-, and 4-picolines as samples.The photo-induced tautomerism of 2-aminopyridine and its derivatives was investigated in a low temperature argon matrix by infrared spectroscopy combined with quantum chemical calculations. The amino tautomer changes to the imino tautomer by UV irradiation (340 >λ【greater than or equal】 300 nm), and the reverse reaction occurs by that with a longer wavelength (370 >λ【greater than or equal】340 nm). Photo-induced transient IR bands assigned to the amino tautomer in the T_1 state were also identified.The relative stabilities of tautomers of 8-oxoguanine (80G) and guanine (G) were investigated comprehensively at various levels of theory. We found that the population of the enol form at C6 position in 80G is higher than that in G at any level of theory which we used. This may partly account for the high mutagenicity of 80GThe solvent-effects on the keto-enol tautomerism of 2-pyridone (2PY) were systematically investigated by infrared spectroscopy and quantum chemical calculations. In a low temperature argon matrix, the keto and enol tautomers of 2PY coexist, while the keto tautomer of 2PY is predominantly observed in the dilute carbon tetrachloride solution at room temperature. The enol tautomer slightly appears as temperature goes up. The tautomerism of 2PY strongly depends on the environment. The stability of the keto tautomer of 2PY predicted by quantum chemical calculation is qualitatively in good agreements with the experimental result.

为了研究辐射引起的 DNA 碱基直接损伤的机制，我们研究了模型分子 2-氨基-3 甲基吡啶在碳和氮 K 边缘的断裂，我们发现在氮 K 壳层电离能发生了特定的反应，其中显着产生了氮原子周围断裂的碎片离子。以 2-、3- 和 4- 甲基吡啶为样品的实验支持了该系统所提出的断裂机制。通过红外光谱结合量子化学计算研究了低温氩基体中2-氨基吡啶及其衍生物的光诱导互变异构现象，在紫外光照射下（340>λ【大于或等于】300）氨基互变异构体转变为亚氨基互变异构体。 nm），波长较长（370>λ【大于等于】340）发生逆反应nm) 还鉴定了属于 T_1 状态的氨基互变异构体的光诱导瞬态红外谱带。我们在不同的理论水平上全面研究了 8-氧代鸟嘌呤 (80G) 和鸟嘌呤 (G) 互变异构体的相对稳定性。在我们使用的任何理论水平上，80G 中 C6 位烯醇形式的数量都高于 G 中的数量，这可能部分解释了 80G 的高致突变性。 80G通过红外光谱和量子化学计算系统研究了溶剂对2-吡啶酮(2PY)酮-烯醇互变异构体的影响。在低温氩基体中，2PY的酮和烯醇互变异构体共存，而2PY的酮互变异构体同时存在。主要在室温下的稀四氯化碳溶液中观察到随着温度升高轻微出现烯醇互变异构体。 2PY的互变异构体强烈依赖于环境，通过量子化学计算预测的2PY酮互变异构体的稳定性与实验结果定性地吻合。

项目成果

期刊论文数量（120）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Crystallization behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) studied by 2D IR correlation spectroscopy

DOI：
10.1016/j.polymer.2004.08.046
发表时间：
2004-09
期刊：
Polymer
影响因子：
4.6
作者：
Adchara Padermshoke;Harumi Sato;Yukiteru Katsumoto;S. Ekgasit;I. Noda;Y. Ozaki
通讯作者：
Adchara Padermshoke;Harumi Sato;Yukiteru Katsumoto;S. Ekgasit;I. Noda;Y. Ozaki

Formation of H_30^+ by the soft X-ray ionization o ethanol clusters

软X射线电离乙醇簇形成H_30^