REACTIVE INTERMEDIATES IN PHOTOCHEMICAL REACTION OF BIOLOGICALLY RELEVANT PURINES

生物相关嘌呤光化学反应中的反应中间体

• 批准号: 6271544
• 负责人: RAFAEL ARCE
• 金额: $ 10.9万
• 依托单位: UNIVERSITY OF PUERTO RICO RIO PIEDRAS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6271544
• 关键词: DNA damage; chemical models; dinucleotide; electron spin resonance spectroscopy; flash photolysis; high performance liquid chromatography; lasers; nuclear magnetic resonance spectroscopy; photoactivation; photochemistry; polynucleotides; purine nucleosides; purine nucleotides; purines; radiobiology; ultraviolet radiation

According to the American Cancer Society, more than 600,000 new cases of skin malignancies will be diagnosed in the U.S. each year. These as well as aging and disorders in the immune system are examples of photooxidatiave modifications to genomic DNA as a result of exposure of living organisms to solar UV radiation. At the molecular level these deleterious effects have been explained in terms of photoinduced base lesions in the nucleic acids. There have been reports of purine photoproducts in UV irradiated DNA which could also lead to these deleterious effects. Stable products of the purine moieties of DNA or reactive intermediates participating in the photochemical processes have not been studied in the same detail as is the case of the pyrimidine bases. In this continuation proposal our main objectives are to: 1. Isolate and characterize the products in the photodestruction mechanism of purine derivatives. These will be correlated to their short lived intermediates already identified and compared to products formed during high intensity nanosecond laser irradiation. 2. Identify intermediates and characterize products in the purine photoinitiated cross-linking reactions with molecules considered to be models for the side chain of amino acids and with amino acids. 3. Study reactions of reactive free radicals produced by the UV photoionization of purines such as the radical cation and the radical anion with biomolecules and to establish their extent of participation in the photodegradation mechanism. All this information will help to understand the role of purines in the DNA photochemistry.

根据美国癌症协会的数据，超过60万例 每年在美国诊断出皮肤恶性肿瘤。 这些 免疫系统中的衰老和疾病也是 暴露于基因组DNA的光氧化剂修饰 生物紫外线辐射的生物体。 在分子水平 这些有害效果已经用照片诱导了 核酸中的碱病变。 有嘌呤的报道 紫外线辐照的DNA中的光产物，这也可能导致这些 有害影响。 DNA或DNA嘌呤部分的稳定产品 参与光化学过程的反应性中间体 尚未与该情况相同的细节研究 嘧啶碱。 在这个延续建议中，我们的主要目标 是： 1。分离并表征在光电隔离中的产品 嘌呤衍生物的机制。 这些将与他们的 已经确定并与产品进行了比较的短期生活中间体 在高强度纳秒激光照射下形成。 2。识别中间体并在嘌呤中表征产品 与被认为是的分子的光学启动交联反应 氨基酸侧链和氨基酸的模型。 3。紫外线产生的反应性自由基的研究反应 嘌呤等嘌呤（例如自由基阳离子和自由基） 带有生物分子的阴离子并确定其参与程度 在光降解机制中。 所有这些信息将有助于 了解嘌呤在DNA光化学中的作用。