Physical approaches to the study of DNA
Physical approaches to the study of DNA
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DOI：
10.1023/b:joss.0000033247.51868.be
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发表时间：
1998-11-01
影响因子：
1.6
通讯作者：
Bensimon, D
中科院分区：
文献类型：
--
作者：
Strick, TR;Allemand, JF;Bensimon, D
新的微操作技术现在使物理学家和生物学家能够研究单个生物分子的行为，如DMA。特别是，测量单个DNA分子对双螺旋超卷曲变化的弹性反应是可能的。扭转松弛DNA的力与延伸图是连续的，并允许人们评估聚合物的持续长度。然而，当分子被超卷曲时，拉伸会导致双螺旋轴上扭转应力的积累。当由此产生的扭转能增加到超过一个临界值时，分子局部不稳定并改变构象。这种结构转变发生在分子马达在体内施加的拉伸力和细胞中发现的超卷曲程度上，可能对细胞核内的DNA结构和功能有影响。
New micromanipulation techniques now enable physicists and biologists to study the behavior of single biomolecules such as DMA. In particular, it is possible to measure the elastic response of individual DNA molecules to changes in the double helix's supercoiling. The force versus extension diagram for torsionally relaxed DNA is continuous and allows one to evaluate the persistence length of the polymer. When the molecule is supercoiled, however, stretching leads to the buildup of torsional stress in the double helix's axis. When the twist energy thus generated increases beyond a critical value, the molecule is locally destabilized and changes conformation. This structural transition occurs at stretching forces which can be exerted in vivo by molecular motors and at degrees of supercoiling found in the cell, and may have implications for DNA structure and function within the nucleus.