Self-attraction and natural curvature in null DNA.
Self-attraction and natural curvature in null DNA.
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无效 DNA 中的自吸引和自然曲率。
DOI：
10.1080/07391102.1989.10507751
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发表时间：
1989
影响因子：
4.4
通讯作者：
Manning,GS
中科院分区：
文献类型：
--
作者：
Manning,GS
当 DNA 的离子电荷被中和时，DNA 固有的自吸引力就会显现出来。在整体层面上，片段之间的自吸引作用将空（电荷中和）DNA 凝结成片段丰富的颗粒。在局部，自吸引倾向于沿其轴线收缩单个节段。如果满足某些条件，压缩段就会从原来的轴线向外弯曲。其最稳定的形状是弯曲的，或者，在极端情况下，甚至是完全折叠的。屈曲条件被导出并显示为 DNA 所满足，从而解释了观察到的浓缩空 DNA 形态中的高度有序曲率和折叠。所采用的中心概念是屈曲持久长度。它针对无效 DNA (40-50 bp) 进行评估，并与实验数据 (<60 bp) 一致。它有助于理解在缩合/解缩平衡中观察到的协同单元（约 60 bp）以及在缩合相中观察到的不稳定消化片段的大小（约 80 bp）。 DNA 中的均方根热压缩/延伸波动估计约为 0.1 Å/bp。
Forces of self-attraction inherent in DNA are unmasked when its ionic charge is neutralized. On the global level, self-attraction operates between segments to condense null (charge-neutralized) DNA into a segment-rich particle. Locally, self-attraction tends to contract an individual segment along its axis. If certain conditions are satisfied, the compressed segment buckles outward from the original line of the axis. Its most stable shape is then curved, or, as an extreme case, even completely folded. Buckling conditions are derived and shown to be met by DNA thus explaining the high degree of ordered curvature and folding in the observed morphologies of condensed null DNA The central concept employed is the buckling persistence length. It is evaluated for null DNA (40–50 bp) and agrees with experimental data (<60 bp). It helps in understanding the observed cooperative unit in the condensation/decondensation equilibrium (about 60 bp) and the observed size of digestion fragments unstable in the condensed phase (about 80 bp). The root-mean-square thermal compression/extension fluctuation in DNA is estimated at about 0.1 Å/bp.