Euler buckling and nonlinear kinking of double-stranded DNA.
Euler buckling and nonlinear kinking of double-stranded DNA.
复制标题
DOI：
10.1093/nar/gkt739
复制
发表时间：
2013-11
影响因子：
14.9
通讯作者：
Cohen AE
中科院分区：
文献类型：
--
作者：
Fields AP;Meyer EA;Cohen AE
双链DNA（dsDNA）在高曲率下的弯曲刚度是其生物活性的基础，然而这种机制难以通过实验进行探测，并且文献结果并不一致。我们创造了一个“分子钳”，其中碱基配对相互作用在dsDNA的亚持久长度片段上产生压缩力。短的dsDNA链（<41个碱基对）抵抗这种力并保持直的;较长的链变得弯曲，这种现象称为“欧拉屈曲”。我们通过附加的荧光团之间的福斯特共振能量转移（FRET）监测屈曲过渡。对于低到中等浓度的单价盐（高达150 mM），我们的结果是在定量协议与蠕虫状链（WLC）模型的DNA弹性，而不需要调用任何'扭结'状态。更高浓度的单价盐或1 mM Mg 2+诱导明显软化的dsDNA，这是最好的占最高曲率的区域中的扭结。我们测试了所有单核苷酸错配对DNA弯曲的影响。值得注意的是，扭结的倾向与相对于完全互补链的错配DNA的热力学不稳定相关，这表明扭结状态是局部熔化的。分子钳对dsDNA的序列依赖性线性和非线性弹性性质非常敏感。
The bending stiffness of double-stranded DNA (dsDNA) at high curvatures is fundamental to its biological activity, yet this regime has been difficult to probe experimentally, and literature results have not been consistent. We created a ‘molecular vise’ in which base-pairing interactions generated a compressive force on sub-persistence length segments of dsDNA. Short dsDNA strands (<41 base pairs) resisted this force and remained straight; longer strands became bent, a phenomenon called ‘Euler buckling’. We monitored the buckling transition via Förster Resonance Energy Transfer (FRET) between appended fluorophores. For low-to-moderate concentrations of monovalent salt (up to ∼150 mM), our results are in quantitative agreement with the worm-like chain (WLC) model of DNA elasticity, without the need to invoke any ‘kinked’ states. Greater concentrations of monovalent salts or 1 mM Mg2+ induced an apparent softening of the dsDNA, which was best accounted for by a kink in the region of highest curvature. We tested the effects of all single-nucleotide mismatches on the DNA bending. Remarkably, the propensity to kink correlated with the thermodynamic destabilization of the mismatched DNA relative the perfectly complementary strand, suggesting that the kinked state is locally melted. The molecular vise is exquisitely sensitive to the sequence-dependent linear and nonlinear elastic properties of dsDNA.
登录
查看更多内容
影响因子：
3.8
作者：
Fenley, MO;Manning, GS;Olson, WK
通讯作者：
Olson, WK
影响因子：
2.4
作者：
Emanuel, Marc;Mohrbach, Herve;Kulic, Igor M.
通讯作者：
Kulic, Igor M.
通过弯曲变形来扭结双螺旋。
影响因子：
14.9
作者：
Du, Quan;Kotlyar, Alexander;Vologodskii, Alexander
通讯作者：
Vologodskii, Alexander
影响因子：
14.9
作者：
Dickerson, RE
通讯作者：
Dickerson, RE
DOI：
10.1073/pnas.0500983102
发表时间：
2005-04-12
影响因子：
11.1
作者：
Du, Q;Smith, C;Vologodskii, A
通讯作者：
Vologodskii, A