1H NMR assignment and melting temperature study of cis-syn and trans-syn thymine dimer containing duplexes of d(CGTATTATGC).d(GCATAATACG).
1H NMR assignment and melting temperature study of cis-syn and trans-syn thymine dimer containing duplexes of d(CGTATTATGC).d(GCATAATACG).
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DOI：
10.1021/bi00489a049
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发表时间：
1990-09
期刊：
影响因子：
2.9
通讯作者：
John-Stephen Taylor;Daniel S. Garrett;I. Brockie;Daniel L. Svoboda;J. Telser
中科院分区：
文献类型：
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作者：
John-Stephen Taylor;Daniel S. Garrett;I. Brockie;Daniel L. Svoboda;J. Telser
描述了含有位点特异性顺式和反式胸腺嘧啶二聚体的双十聚体的制备和光谱表征。三种双链十聚体d（CGTATTATGC）.d（GCATAATACG）、d（CGTAT[c，s]TATGC）.d（GCATAATACG）和d（CGTAT[t，s]TATGC）.d（GCATAATACG）通过固相亚磷酰胺合成利用顺式和反式-顺式环丁烷胸腺嘧啶二聚体结构单元来制备（Taylor等人，1987; Taylor & Brockie，1988）。NMR谱（500 MHz 2D 1H和202 MHz 1D 31 P）在10 ℃下在“100%”D2 O中获得，1D可交换1H谱在10 ℃下在10% D2 O中获得。基于标准顺序NOE分配策略对H5、H6、H8、CH 3、H1 '、H2'和H2”进行1H NMR分配，并通过DQF COSY数据进行部分验证。化学位移数据的比较表明，螺旋结构的扰动更多的顺式-syn二聚体的3 '-侧和更多的反式-syn二聚体的5'-侧。通过对双链体的熔融行为进行双态（全态或无态）分析，获得了处于平衡卷曲平衡的螺旋的热力学参数。对T5 CH 3 1H NMR信号的温度依赖性的分析给出反式-顺式双链体的Δ H = 44 +/- 4 kcal和Δ S = 132 +/- 13 eu。对UV光谱的浓度和温度依赖性的分析给出了亲本双链体的Δ H = 64 +/- 6 kcal和Δ S = 178 +/- 18 eu，以及顺式-顺式双链体的Δ H = 66 +/- 7 kcal和Δ S = 189 +/- 19 eu。得出的结论是，dTpdT单元的光二聚化产生顺式-syn产物引起的DNA扰动很小，而二聚化产生反式-syn产物引起的扰动大得多，可能是在二聚体的5 '侧的扭结或位错的形式。
The preparation and spectroscopic characterization of duplex decamers containing site-specific cis-syn and trans-syn thymine dimers are described. Three duplex decamers, d(CGTATTATGC).d(GCATAATACG), d(CGTAT[c,s]TATGC).d(GCATAATACG), and d(CGTAT[t,s]TATGC).d(GCATAATACG), were prepared by solid-phase phosphoramidite synthesis utilizing cis-syn and trans-syn cyclobutane thymine dimer building blocks (Taylor et al., 1987; Taylor & Brockie, 1988). NMR spectra (500 MHz 2D 1H and 202 MHz 1D 31P) were obtained in "100%" D2O at 10 degrees C, and 1D exchangeable 1H spectra were obtained in 10% D2O at 10 degrees C. 1H NMR assignments for H5, H6, H8, CH3, H1', H2', and H2" were made on the basis of standard sequential NOE assignment strategies and verified in part by DQF COSY data. Comparison of the chemical shift data suggests that the helix structure is perturbed more to the 3'-side of the cis-syn dimer and more to the 5'-side of the trans-syn dimer. Thermodynamic parameters for the helix in equilibrium coil equilibrium were obtained by two-state, all or none, analysis of the melting behavior of the duplexes. Analysis of the temperature dependence of the T5CH3 1H NMR signal gave delta H = 44 +/- 4 kcal and delta S = 132 +/- 13 eu for the trans-syn duplex. Analysis of the concentration and temperature dependence of UV spectra gave delta H = 64 +/- 6 kcal and delta S = 178 +/- 18 eu for the parent duplex and delta H = 66 +/- 7 kcal and delta S = 189 +/- 19 eu for cis-syn duplex. It was concluded that photodimerization of the dTpdT unit to give the cis-syn product causes little perturbation of the DNA whereas dimerization to give the trans-syn product causes much greater perturbation, possibly in the form of a kink or dislocation at the 5'-side of the dimer.