Single-molecule dissection of stacking forces in DNA
Single-molecule dissection of stacking forces in DNA
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DOI：
10.1126/science.aaf5508
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发表时间：
2016-09-09
期刊：
影响因子：
56.9
通讯作者：
Dietz, Hendrik
中科院分区：
文献类型：
--
作者：
Kilchherr, Fabian;Wachauf, Christian;Dietz, Hendrik
我们直接测量在单分子水平上的力量和寿命的DNA碱基对堆叠相互作用的所有堆栈序列组合。我们的实验方法结合了双光束光镊与DNA折纸组件，以允许定位钝端DNA螺旋，以便可以分离出弱的堆叠力。缺乏共价骨架连接的碱基对堆叠阵列自发地以每秒0.02至500的平均速率解离，这取决于序列组合和堆叠阵列大小。力的范围从2到8皮牛顿，作用沿着螺旋方向只是温和地加速随机解堆过程。我们从测量的向前和向后的动力学速率估计的每堆叠的自由能增量范围从-0.8到-3.4千卡每摩尔，取决于序列组合。我们的数据有助于理解生物学中DNA加工的机制，并有助于根据用户规格设计基于DNA的纳米级器件的动力学。
We directly measured at the single-molecule level the forces and lifetimes of DNA base-pair stacking interactions for all stack sequence combinations. Our experimental approach combined dual-beam optical tweezers with DNA origami components to allow positioning of blunt-end DNA helices so that the weak stacking force could be isolated. Base-pair stack arrays that lacked a covalent backbone connection spontaneously dissociated at average rates ranging from 0.02 to 500 per second, depending on the sequence combination and stack array size. Forces in the range from 2 to 8 piconewtons that act along the helical direction only mildly accelerated the stochastic unstacking process. The free-energy increments per stack that we estimate from the measured forward and backward kinetic rates ranged from -0.8 to -3.4 kilocalories per mole, depending on the sequence combination. Our data contributes to understanding the mechanics of DNA processing in biology, and it is helpful for designing the kinetics of DNA-based nanoscale devices according to user specifications.