Salt-induced changes in plasmid DNA transmission through ultrafiltration membranes
Salt-induced changes in plasmid DNA transmission through ultrafiltration membranes
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DOI：
10.1002/bit.21575
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发表时间：
2008-02-01
影响因子：
3.8
通讯作者：
Zydney, Andrew L.
中科院分区：
文献类型：
--
作者：
Latulippe, David R.;Zydney, Andrew L.
最近的研究已经证明了使用超滤纯化质粒DNA的可行性，但仍然很少了解的因素，支配DNA的传输。在搅拌超滤池中，获得了3.0 kbp超螺旋质粒DNA通过复合再生纤维素超滤膜的传输作为溶液离子环境的函数的实验数据。盐浓度的依赖性是相当戏剧性的，与筛分系数增加了80倍以上的NaCl浓度从1增加到150 mM，在一个固定的滤液通量。在相同的总离子强度下，MgCl2溶液中的筛分系数显著大于NaCl溶液中的筛分系数。筛分结果与独立研究一致，表明由于盐特异性屏蔽分子内静电相互作用，有效质粒大小减少。DNA传输也是滤液通量的强函数，在通量的临界值以下传输可忽略不计。用改进的拉伸流动模型预测的临界过滤通量与实验值吻合得很好。这些结果清楚地表明，盐诱导的质粒DNA结构的变化对质粒DNA通过超滤膜的传输有显着影响。
Recent studies have demonstrated the feasibility of using ultrafiltration for the purification of plasmid DNA, but there is still little understanding of the factors governing DNA transmission. Experimental data were obtained for the transmission of a 3.0 kbp supercoiled plasmid DNA through composite regenerated cellulose ultrafiltration membranes as a function of solution ionic environment in a stirred ultrafiltration cell. The dependence on salt concentration was quite dramatic, with the sieving coefficient increasing by more than 80-fold as the NaCl concentration increased from 1 to 150 mM at a fixed filtrate flux. At the same total ionic strength, the sieving coefficient in an MgCl2 solution was significantly larger than that evaluated in NaCl. The sieving results are consistent with independent studies showing a reduction in the effective plasmid size due to salt specific shielding of intramolecular electrostatic interactions. DNA transmission was also a strong function of the filtrate flux, with negligible transmission below a critical value of the flux. The predicted values of the critical filtrate flux determined using a modified elongational flow model were in excellent agreement with the experimental data. These results clearly demonstrate that salt-induced changes in plasmid DNA structure have a significant effect on plasmid DNA transmission through ultrafiltration membranes.