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紫外线(UV)辐射是自然环境中重要的DNA致伤因子。UV辐射在DNA造成的最主要一类损伤产物是环丁烷嘧啶二聚体(pyrim-idine dimer,PD),它是由DNA中一条多核着酸链上两相邻嘧啶碱基各自的C5和C6共价连接形成的环丁烷结构。哺乳动物细胞主要通过切除修复途径移除PD,恢复DNA的正常结构。一种从噬菌体T4感染的E.coli中提取的T4核酸内切酶V(EndoV)能特异识别PD,并在该损伤位点切断磷酸二醋键,造成单链断裂。本文即以EndoV为探针,以其敏感位点(endonuclease-sensitive-site,ESS)
Ultraviolet (UV) radiation is an important DNA damage factor in the natural environment. The most important type of damage product caused by UV radiation in DNA is the pyrimidine dimer (PD), which is composed of two adjacent pyrimidine bases on a polynucleic acid chain in the DNA and C5. The cyclobutane structure formed by the covalent linkage of C6. Mammalian cells mainly remove PD through the excision repair pathway, restoring the normal structure of DNA. A T4 endonuclease V (EndoV) extracted from bacteriophage T4-infected E.coli can specifically recognize PD and cut the phosphodiester bond at this site of injury, resulting in a single-strand break. This article uses EndoV as a probe and its sensitive site (endonuclease-sensitive-site, ESS).