Molecular mechanisms and kinetics between DNA and DNA binding ligands
Molecular mechanisms and kinetics between DNA and DNA binding ligands
复制标题
DOI：
10.1529/biophysj.103.036293
复制
发表时间：
2005-01-01
影响因子：
3.4
通讯作者：
Anselmetti, D
中科院分区：
文献类型：
--
作者：
Sischka, A;Toensing, K;Anselmetti, D
在亚皮牛顿力分辨的光钳实验中，分析了不同结合配体存在下单双链DNA(DsDNA)的力学性质。配体与DNA的结合改变了dsDNA分子的整体机械反应。这一基本性质可用于区分和鉴定不同的结合模式，而且可能与核小体包装等各种过程或癌症治疗等应用有关。我们比较了小沟槽结合剂地沙霉素-A(一种主要沟槽结合的α-螺旋多肽)、插入剂溴化乙锭、YO-1和柔红霉素以及双嵌入剂YOYO-1对lambda-DNA的影响。与可检测到的游离dsDNA相比，分子与dsDNA的小槽和大槽的结合引起了分子弹性的明显变化，这是过度拉伸转变到更高作用力的转变。插层分子通过完全消除B-S跃迁和相应的分子轮廓长度增加来影响分子力学。在拉伸/松弛循环中，YOYO-1的速度为>；10 nm/S，柔红霉素的速度为>；1000 nm/S。这分别表明YOYO-DNA和柔红霉素-DNA复合体在分钟和秒的时间尺度上的结构变化。
Mechanical properties of single double-stranded DNA ( dsDNA) in the presence of different binding ligands were analyzed in optical-tweezers experiments with subpiconewton force resolution. The binding of ligands to DNA changes the overall mechanic response of the dsDNA molecule. This fundamental property can be used for discrimination and identification of different binding modes and, furthermore, may be relevant for various processes like nucleosome packing or applications like cancer therapy. We compared the effects of the minor groove binder distamycin-A, a major groove binding alpha-helical peptide, the intercalators ethidium bromide, YO-1, and daunomycin as well as the bisintercalator YOYO-1 on lambda-DNA. Binding of molecules to the minor and major groove of dsDNA induces distinct changes in the molecular elasticity compared to the free dsDNA detectable as a shift of the overstretching transition to higher forces. Intercalating molecules affect the molecular mechanics by a complete disappearance of the B-S transition and an associated increase in molecular contour length. Significant force hysteresis effects occurring during stretching/relaxation cycles with velocities >10 nm/s for YOYO-1 and >1000 nm/s for daunomycin. These indicate structural changes in the timescale of minutes for the YOYO-DNA and of seconds for the daunomycin-DNA complexes, respectively.