EVIDENCE FROM BASE-PAIR KINETICS FOR 2 TYPES OF ADENINE TRACT STRUCTURES IN SOLUTION - THEIR RELATION TO DNA CURVATURE
EVIDENCE FROM BASE-PAIR KINETICS FOR 2 TYPES OF ADENINE TRACT STRUCTURES IN SOLUTION - THEIR RELATION TO DNA CURVATURE
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DOI：
10.1021/bi00425a004
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发表时间：
1988-12-13
期刊：
影响因子：
2.9
通讯作者：
GUERON, M
中科院分区：
文献类型：
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作者：
LEROY, JL;CHARRETIER, E;GUERON, M
我们用亚氨基质子磁共振测量了含有A. cnt.T碱基对的寡脱氧核苷酸的碱基对寿命。当该片段含有多于四个连续的A → T碱基对时，可能包括5 ″-AT步骤但不包括5 ″-TA步骤，观察到异常长的寿命。例如，十二聚体5 ″-d-CGCAAAAAAGCG的中心A·T碱基对的寿命在15 ℃下为122和91 ms。而在相同条件下，去琥珀5 ″-d-CGCGATCGCG的中心A.T对的寿命仅为4 ms，该值类似于在几种其它B-DNA寡双链体中测得的值[Leroy等（1988）J. Mol. 200，223-238]。这有力地表明，在四对或更多的A. T对的片段中，协同形成了不同于标准B-DNA的构象。所有已知能产生弯曲DNA的序列都表现出超长的碱基对寿命。这是第一个与DNA曲率相关的局部和物理性质。我们的观察表明，负责长寿命的结构与DNA的曲率有关。
We have measured the base-pair lifetimes in oligodeoxynucleotides containing tracts of A.cntdot.T base pairs using imino proton magnetic resonance. When the tract contains more than four consecutive A.cntdot.T base pairs, possibly including a 5''-AT step but not a 5''-TA step, anomalously long lifetimes are observed. For example, the lifetimes of the central A.cntdot.T base pairs of the dodecamer 5''-d-CGCAAAAAAGCG are 122 and 91 ms at 15.degree. C whereas, in the same conditions, the lifetime of the central A.cntdot.T pair of the decamber 5''-d-CGCGATCGCG is only 4 ms, a value similar to those measured in several other B-DNA oligoduplexes [Leroy et al. (1988) J. Mol. Biol. 200, 223-238]. This strongly suggests that, in tracts of four A.cntdot.T pairs or more, a conformation distinct from standard B-DNA is formed cooperatively. All sequences known to generate curved DNA exhibit anomalously long base-pair lifetimes. This is the first local and physical property shown to correlate with DNA curvature. Our observations suggest that the structure responsible for the long lifetimes is involved in the curvature of DNA.