Unusual conformational effect exerted by Z-DNA upon its neighboring sequences.
Unusual conformational effect exerted by Z-DNA upon its neighboring sequences.
复制标题
Z-DNA 对其邻近序列产生不寻常的构象效应。
DOI：
10.1073/pnas.84.8.2223
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发表时间：
1987
影响因子：
11.1
通讯作者：
Kohwi,Y
中科院分区：
文献类型：
--
作者：
Kohwi-Shigematsu,T;Manes,T;Kohwi,Y
带有 (dG-dC)16 插入片段（已知在负超螺旋时形成 Z-DNA 的序列）的超螺旋质粒 DNA 与氯乙醛反应。氯乙醛与溴乙醛一样，被发现是检测超螺旋质粒 DNA 中不配对 DNA 碱基的特异性探针。在扭转应力下（在细菌超螺旋密度下），氯乙醛在 (dG-dC)16 插入物的相邻序列内的多个离散区域发生反应。当将质粒群体视为一个整体时，化学反应碱基的分布表现出反转对称模式，反转中心位于 (dG-dC)16 插入片段的中间。然而，当考虑单个超螺旋质粒分子时，氯乙醛仅与相邻序列之一（(dG-dC)16 插入物的 5' 或 3' 反应），但不与两者反应。讨论了超螺旋质粒 DNA 与这两种结构形式处于平衡状态的可能性。
Supercoiled plasmid DNA harboring an insert of (dG-dC)16, a sequence known to form Z-DNA upon negative supercoiling, was reacted with chloroacetaldehyde. Chloroacetaldehyde, like bromoacetaldehyde, was found to be a specific probe for detecting unpaired DNA bases in supercoiled plasmid DNA. Under torsional stress (at bacterial superhelical density), chloroacetaldehyde reacted at multiple discrete regions within the neighboring sequences of the (dG-dC)16 insert. When the plasmid population was considered as a whole, the distribution of the chemically reactive bases exhibited a pattern of inversion symmetry with the center of inversion in the middle of the (dG-dC)16 insert. However, when a single supercoiled plasmid molecule was considered, chloroacetaldehyde reacted with only one of the neighboring sequences, either 5' or 3' of the (dG-dC)16 insert, but not with both. The possibility that the supercoiled plasmid DNA is in equilibrium with these two structural forms is discussed.