THE 3-WAY DNA JUNCTION IS A Y-SHAPED MOLECULE IN WHICH THERE IS NO HELIX HELIX STACKING
THE 3-WAY DNA JUNCTION IS A Y-SHAPED MOLECULE IN WHICH THERE IS NO HELIX HELIX STACKING
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DOI：
10.1002/j.1460-2075.1990.tb08286.x
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发表时间：
1990-05-01
期刊：
影响因子：
11.4
通讯作者：
LILLEY, DMJ
中科院分区：
文献类型：
--
作者：
DUCKETT, DR;LILLEY, DMJ
我们已经研究了一些三向DNA连接的结构，这些连接在序列上与以前研究的四向连接密切相关。我们观察到，通过选择性缩短一个臂的结所得到的物种的电泳迁移率是非常相似的，无论臂被缩短，这仍然是如此，无论镁是否存在于缓冲液中。这表明三路交叉点的臂之间的夹角是相似的。所有的胸腺嘧啶基地立即位于交界处的反应，四氧化锇，表明平面外的攻击是不阻止螺旋-螺旋堆积，这也是独立的存在或不存在的金属阳离子。结果表明，三路连接不能进行离子诱导的构象折叠，包括螺旋堆积，但仍然固定在一个Y形的扩展构象。因此，在阳离子存在的情况下，三通和四通接头的性质是完全不同的。
We have studied the structure of a number of three-way DNA junctions that were closely related in sequence to four-way junctions studied previously. We observe that the electrophoretic mobility of the species derived by selective shortening of one arm of a junction are very similar whichever arm is shortened, and that this remains so whether or not magnesium is present in the buffer. This suggests that the angles subtended between the arms of the three-way junctions are similar. All thymine bases located immediately at the junction are reactive to osmium tetroxide, indicating that out-of-plane attack is not prevented by helix-helix stacking, and this is also independent of the presence or absence of metal cations. The results suggest that the three-way junction cannot undergo an ion-induced conformational folding involving helical stacking, but remains fixed in a Y-shaped extended conformation. Thus the three- and four-way junctions are quite different in character in the presence of cations.