Base stacking and unstacking as determined from a DNA decamer containing a fluorescent base.
Base stacking and unstacking as determined from a DNA decamer containing a fluorescent base.
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DOI：
10.1021/bi00479a024
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发表时间：
1990-07
期刊：
影响因子：
2.9
通讯作者：
Pengguang Wu;T. Nordlund;B. Gildea;L. McLaughlin
中科院分区：
文献类型：
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作者：
Pengguang Wu;T. Nordlund;B. Gildea;L. McLaughlin
在几个温度下测量并分析单链DNA十聚体d（CTGAAT 5CAG）的时间分辨荧光衰减，其中d5是荧光碱基1-（β-D-2 '-脱氧核糖基）-5-甲基-2-嘧啶酮。在十聚体的d5基地被分解成三种状态，根据他们的荧光衰减寿命特性和温度依赖性的相关振幅：完全扩展和完全非堆叠状态，松散关联状态，和完全堆叠状态。与它们的荧光衰减速率相比，这些状态处于缓慢的交换中。完全扩展和完全非堆叠状态的人口是小的，并随着温度的升高而进一步减少。松散缔合状态，其荧光仍然可以被其他DNA碱基有效地猝灭，占据了传统定义的非堆叠状态的大部分。计算出DNA十聚体中d5碱基与胸腺嘧啶或胞嘧啶碱基的堆积焓和熵分别为-6.6 kcal/mol和-22 cal/mol.K。这项工作表明，DNA中的荧光碱基可以用于碱基局部构象的研究。
Time-resolved fluorescence decay of a single-stranded DNA decamer d(CTGAAT5CAG), where d5 is the fluorescent base 1-(beta-D-2'-deoxyribosyl)-5-methyl-2-pyrimidinone, was measured and analyzed at several temperatures. The d5 base in the decamer is resolved into three states according to their fluorescence decay lifetime characteristics and temperature dependence of their associated amplitudes: fully extended and completely unstacked state, loosely associated state, and fully stacked state. These states are in slow exchange compared to their fluorescence decay rates. The population of the fully extended and completely unstacked state is small and decreases further with increasing temperature. The loosely associated state, whose fluorescence can still be efficiently quenched by other DNA bases, occupies a large portion of the conventionally defined unstacked state. Stacking enthalpy and entropy for the d5 base with thymine or cytosine bases in the DNA decamer are calculated to be -6.6 kcal/mol and -22 cal/mol.K, respectively. This work shows that fluorescent bases in DNA can be useful to the study of local conformations of bases.