AN IMMOBILE NUCLEIC-ACID JUNCTION CONSTRUCTED FROM OLIGONUCLEOTIDES
AN IMMOBILE NUCLEIC-ACID JUNCTION CONSTRUCTED FROM OLIGONUCLEOTIDES
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DOI：
10.1038/305829a0
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发表时间：
1983-01-01
期刊：
影响因子：
64.8
通讯作者：
SEEMAN, NC
中科院分区：
文献类型：
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作者：
KALLENBACH, NR;MA, RI;SEEMAN, NC
涉及寡核苷酸模型系统的碱基配对DNA双链提供了有关双螺旋结构的详细结构和动态信息的主要来源1。DNA的三分支和四分支“连接”结构作为DNA分子复制或重组的中间产物而存在2-5，而十字形可能被负超卷闭合环状DNA6-11诱导。然而，在短链分子中，这些形式的结构还不可能在高分辨率下进行研究，其中连接将产生信号的重要组成部分，因为这些自然产生的中间产物本质上是不稳定的，这是由于内部序列对称性，这使得它们可以通过分支点迁移12-15分解为双螺旋。我们最近提出，通过结合序列对称性约束和平衡计算，可以消除迁移以从寡核苷酸DNA16-19获得固定连接。我们在这里给出了电泳和紫外光吸收实验，表明四个十六碳氧基核苷酸(图1)在溶液中确实形成了一个稳定的四聚体连接络合物。
Base-paired DNA duplexes involving oligonucleotide model systems have provided the major source of detailed structural and dynamic information about double helical structure1. Triple- and quadruple-branched ‘junction’ structures of DNA have a transient existence as intermediates in the replication or recombination of DNA molecules2–5while cruciforms may be inducible by negatively supercoiling closed circular DNA6–11. However, it has not been possible to investigate these forms structurally at high resolution in short-chain molecules, where the junction will yield a significant component of the signal, because these naturally occurring intermediates are inherently unstable, due to internal sequence symmetry, which permits their resolution to double helices, via branchpoint migration12–15. We have recently proposed that migration can be eliminated to yield immobile junctions from oligonucleotides16–19by combining sequence symmetry constraints with equilibrium calculations. We present here electrophoretic and UV optical absorbance experiments which indicate that four hexadecadeoxynucleotides (Fig. 1) indeed do form a stable tetrameric junction complex in solution.