Relaxation effects in the gel electrophoresis of DNA in intermittent fields.
Relaxation effects in the gel electrophoresis of DNA in intermittent fields.
复制标题
间歇场中 DNA 凝胶电泳的弛豫效应。
DOI：
10.1002/bip.360280807
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发表时间：
1989
期刊：
影响因子：
2.9
通讯作者：
Lerman,LS
中科院分区：
文献类型：
--
作者：
Jamil,T;Frisch,HL;Lerman,LS
如果电场是间歇性的而不是连续的，则琼脂糖凝胶中 lambda DNA 限制性片段的电泳迁移率会下降，对较长片段的影响更大。这些变化与场相关构型变化的两个指数弛豫过程的假设兼容，一个在场打开时，另一个在场终止时。当分子构型不受电场影响时，长间隔短脉冲的迁移率外推极限的长度依赖性与从理论考虑中预期的简单反比关系密切相关。简单的间歇场可以分离比通常可以解析的更长的分子。场引起的构象变化和返回无场构象的弛豫时间大约以分子长度的二次方变化，与盐浓度或场强无关，并且仅随凝胶密度略有变化。这些关系与蠕动理论预期的特性不太一致，并且它们表明必须调用不同的机制来实现长 DNA 分子在普通场强值下的电泳迁移。
The electrophoretic mobility of restriction fragments of lambda DNA in agarose gels declines if the field is intermittent rather than continuous, with a greater effect on the longer fragments. The changes are compatible with the assumption of two exponential relaxation processes for field‐dependent configurational changes, one when the field is turned on and another when it terminates. The length dependence at the extrapolated limit of mobility for short pulses with long intervals corresponds closely to the simple inverse proportionality to length expected from theoretical considerations when the molecular configuration is not affected by the electric field. Simple intermittent fields would allow separation of longer molecules than can ordinarily be resolved. The relaxation times for both the change in conformation imposed by the field and the return to field‐free conformation vary as approximately the second power of the length of the molecule, independent of the salt concentration or field strength and varying only slightly with gel density. These relations are not in good agreement with properties expected from reptation theory, and they suggest that a different mechanism must be invoked for the electrophoretic migration of long DNA molecules at ordinary values of field strength.