FTIR study of light-dependent activation and DNA repair processes of (6-4) photolyase.
FTIR study of light-dependent activation and DNA repair processes of (6-4) photolyase.
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(6-4) 光裂合酶的光依赖性激活和 DNA 修复过程的 FTIR 研究。
DOI：
10.1021/bi1019397
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发表时间：
2011
期刊：
影响因子：
2.9
通讯作者：
Kandori,Hideki
中科院分区：
文献类型：
--
作者：
Zhang,Yu;Iwata,Tatsuya;Yamamoto,Junpei;Hitomi,Kenichi;Iwai,Shigenori;Todo,Takeshi;Getzoff,ElizabethD;Kandori,Hideki
太阳光的紫外线成分通过破坏DNA威胁地球上的所有生命。光解酶（PHR）DNA修复蛋白通过利用蓝光从主要UV诱导的光产物、环丁烷嘧啶二聚体（CPD）和（6-4）光产物（（6 -4）PP）恢复完整碱基来维持遗传完整性。（6-4）PHR不仅要催化两个嘧啶碱基之间的共价键断裂，还要催化羟基或氨基从5′-嘧啶碱基转移到3′-嘧啶碱基，这需要一个比CPD PHR所假设的更复杂的机理。本文将傅里叶变换红外（FTIR）光谱应用于（6-4）PHR，报道了与其光活化、底物结合、和依赖光的DNA修复过程。携带单个（6-4）PP的DNA的存在独特地影响蛋白质骨架和质子化羧酸的振动，而光活化产生FAD辅因子和周围蛋白质的IR光谱变化。光依赖性DNA损伤修复反应的差示FTIR光谱直接显示了（6-4）损伤和邻近磷酸基团的显著DNA结构变化。时间依赖性照明的样品与不同的酶：底物化学计量成功区分信号特征的结构变化的蛋白质和DNA的结合和催化。
The UV component of sunlight threatens all life on the earth by damaging DNA. The photolyase (PHR) DNA repair proteins maintain genetic integrity by harnessing blue light to restore intact bases from the major UV-induced photoproducts, cyclobutane pyrimidine dimers (CPD), and (6–4) photoproducts ((6–4) PPs). The (6–4) PHR must catalyze not only covalent bond cleavage between two pyrmidine bases but also hydroxyl or amino group transfer from the 5′- to 3′-pyrimidine base, requiring a more complex mechanism than that postulated for CPD PHR. In this paper, we apply Fourier transform infrared (FTIR) spectroscopy to (6–4) PHR and report difference FTIR spectra that correspond to its photoactivation, substrate binding, and light-dependent DNA repair processes. The presence of DNA carrying a single (6–4) PP uniquely influences vibrations of the protein backbone and a protonated carboxylic acid, whereas photoactivation produces IR spectral changes for the FAD cofactor and the surrounding protein. Difference FTIR spectra for the light-dependent DNA damage repair reaction directly show significant DNA structural changes in the (6–4) lesion and the neighboring phosphate group. Time-dependent illumination of samples with different enzyme:substrate stoichiometries successfully distinguished signals characteristic of structural changes in the protein and the DNA resulting from binding and catalysis.