THERMODYNAMIC PROPERTIES OF EXOCYCLIC DNA ADDUCTS

外环 DNA 加合物的热力学性质

• 批准号: 6416843
• 负责人: KENNETH J. BRESLAUER
• 金额: $ 11.52万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-01 至 2002-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6416843
• 关键词: DNA damage; adduct; calorimetry; chemical models; chemical stability; chemical structure function; molecular dynamics; mutagens; nuclear magnetic resonance spectroscopy; nucleic acid sequence; nucleic acid structure; oxidation; synthetic nucleic acid; thermodynamics

DESCRIPTION: (Applicant's Description) During the current funding period, we have applied spectroscopic and calorimetric techniques to characterize the thermal (delta Go, delta Ho, delta So, delta Cp) and extra-thermodynamic impacts of mutagenic lesions on the stabilities, conformational preferences, temperature-dependent transitions, and melting cooperativities of DNA duplexes. Our program for the requested funding period is divided into two parts, to be pursued in parallel. In Part I, we will build on our embryonic database for lesion-containing DNA duplexes by evaluating: (i) the communication of lesion effects through the DNA backbone and/or stacked bases; (ii) the impact of lesions on the length and flexibility of DNA; (iii) a new fluorescence-based methodology for rapid and reliable determination of DNA duplex stabilities; and (iv) the impact of additional lesions on the physicochemical properties of DNA duplexes, particularly interstrand crosslinks, FapydG, the major acrolein adduct of guanine, and the carbocyclic analogs of dA, 8-oxodG and the abasic site. The effects of sequence context (cross-strand partner bases and flanking bases) on the thermodynamic and extra-thermodynamic impacts of these lesions will be assessed with an eye towards further evaluating the role of "energetic discrimination/recognition" of structurally similar DNA domains. In Part II of our program, we will use calorimetric methods (i) to define the energetic landscape of template-directed DNA synthesis by an exonuclease deficient Klenow fragment of E. coli polymerase I and (ii) to characterize the thermodynamics of repair protein recognition of damage in DNA. These efforts are designed to define lesion-induced physicochemical differences that may provide the basis for selective recognition of damaged DNA sites by the machinery of repair. Our ultimate goal is to use our spectroscopic and calorimetric results, together with NMR studies, to define relationships between structure, energetics, and biological activity. Such correlations should help us elucidate mechanisms of chemical and radiation induced mutagenesis, lesion recognition, and repair.

描述：（申请人的描述）在当前的资金期间，我们应用了光谱和量热学技术来表征热量（Delta GO，Delta Ho，Delta So，Delta So，Delta CP）和诱变病变对稳定性，结构性偏好，温度依赖性过渡性和恋爱的刺激性病变的热动力学影响。我们要求的资金期限的计划分为两个部分，并并行追求。 在第一部分中，我们将通过评估：（i）通过DNA骨干和/或堆叠的碱基的胚胎效应来构建含有病变DNA双链体的胚胎数据库； （ii）病变对DNA的长度和柔韧性的影响； （iii）一种基于荧光的新方法，用于快速可靠地确定DNA双链稳定性； （iv）其他病变对DNA双链体的物理化学特性的影响，尤其是链间交叉链接，FapyDG，鸟嘌呤的主要丙烯醛加合物以及DA，8-OXODG和ABASIC部位的DA，8-Oxodg和Abasic位点的碳环类似物。 序列环境（跨链伴侣基碱基和侧翼基碱基）对这些病变的热力学和热动力学影响的影响将进行评估，以进一步评估结构上相似的DNA领域的“能量歧视/识别”的作用。在我们程序的第二部分中，我们将使用量热法（i）来定义模板指导的DNA合成的能量景观，这是通过外核酶缺乏大肠杆菌聚合酶I和（ii）的表征来表征DNA损伤的修复蛋白识别损害的热力学的表征。 这些努力旨在定义病变引起的物理化学差异，这可能为通过修复机制选择性识别受损的DNA位点的基础。我们的最终目标是使用我们的光谱和量热结果以及NMR研究来定义结构，能量学和生物学活性之间的关系。 这种相关性应有助于我们阐明化学和辐射引起的诱变，病变识别和修复机制。