Coexistence of coil and globule domains within a single confined DNA chain.
Coexistence of coil and globule domains within a single confined DNA chain.
复制标题
线圈和球域在单个密闭DNA链中的共存。
DOI：
10.1093/nar/gkv1494
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发表时间：
2016-02-18
影响因子：
14.9
通讯作者：
Livolant F
中科院分区：
文献类型：
--
作者：
Sung B;Leforestier A;Livolant F
高度带电的DNA链可以是伸展的构象，即螺旋，也可以是浓缩成高度密集和有序的结构，即环形。这种转变，也称为链的崩溃，可以以不同的方式触发，例如通过改变溶液的离子条件。我们一个接一个地观察单个DNA分子，这些分子被隔离并限制在蛋白质外壳（细菌病毒的包膜，直径80 nm）内。对于亚临界浓度的精胺（4+），DNA的一部分被浓缩并组织成环状，而链的另一部分保持未浓缩。两种状态沿着同一条DNA链共存。这些“毛状”小球通过冷冻电子显微镜成像。我们描述的全球构象的链和局部有序的DNA片段内的环形。
The highly charged DNA chain may be either in an extended conformation, the coil, or condensed into a highly dense and ordered structure, the toroid. The transition, also called collapse of the chain, can be triggered in different ways, for example by changing the ionic conditions of the solution. We observe individual DNA molecules one by one, kept separated and confined inside a protein shell (the envelope of a bacterial virus, 80 nm in diameter). For subcritical concentrations of spermine (4+), part of the DNA is condensed and organized in a toroid and the other part of the chain remains uncondensed around. Two states coexist along the same DNA chain. These ‘hairy’ globules are imaged by cryo-electron microscopy. We describe the global conformation of the chain and the local ordering of DNA segments inside the toroid.