Effects of contact force and salt concentration on the unbinding of a DNA duplex by force spectroscopy
Effects of contact force and salt concentration on the unbinding of a DNA duplex by force spectroscopy
复制标题
DOI：
10.1021/la0523560
复制
发表时间：
2006-01-31
期刊：
影响因子：
3.9
通讯作者：
Sinniah, K
中科院分区：
文献类型：
--
作者：
Wal, MV;Kamper, S;Sinniah, K
我们报告说，不同的接触力的力谱结果在DNA的解结合力，从短的寡核苷酸使用PicoForce显微镜测量的显着转变。30-mer互补DNA包被的探针和表面之间的接触力从100 pN变化到10 nN，导致在双链体之间测量的最丰富的解结合力的显着变化。当接触力设定在200 pN或更低时，这通常被认为是生物分子力光谱研究的低接触力区域，DNA解结合力的变化随着接触力的变化而显著。还在5至500 mM的盐浓度范围内检查了盐浓度对DNA解结合力的影响，因为盐离子的存在对于促进杂交过程是必要的。虽然盐浓度的增加导致在力谱测量过程中的DNA多重结合事件的促进，未观察到显着的变化，在解束缚力。我们的实验表明，文献中报道的短寡核苷酸的DNA解结合力的广泛变化（50-600 pN）可以通过使用的不同接触力来解释，并且在这些研究中使用的盐浓度几乎没有影响。此外，这项研究表明，报告接触力的重要性，在力谱测量不同的生物分子系统之间的定量比较，特别是非共价型相互作用。
We report that varying the contact force in force spectroscopy results in a significant shift in DNA unbinding forces, measured from short oligonucleotides using a PicoForce microscope. The contact force between a 30-mer complementary DNA-coated probe and surface was varied from 100 pN to 10 nN, resulting in a significant shift in the most abundant unbinding force measured between the duplex. When contact forces were set at 200 pN or less, which is generally considered to be a low contact force region for biomolecular force spectroscopy studies, the shift in DNA unbinding forces was significant with changes in contact force. The effect of the salt concentration on the DNA unbinding forces was also examined for a range of salt concentrations from 5 to 500 mM because the presence of salt ions is necessary to facilitate the hybridization process. Although an increase in salt concentration resulted in the facilitation of DNA multiple binding events during force spectroscopy measurements, no significant shift in unbinding forces was observed. Our experiment demonstrates that the wide variation in DNA unbinding forces reported in the literature (50-600 pN) for short oligonucleotides can be accounted for by the different contact forces used and shows little or no effect of the salt concentration used in those studies. Furthermore, this study demonstrates the importance of reporting contact forces in force spectroscopy measurements for quantitative comparisons between different biomolecular systems, especially for noncovalent-type interactions.