Ma C, Bloomfield V A
Department of Biochemistry, University of Minnesota, St. Paul 55108.
Biopolymers. 1995 Feb;35(2):211-6. doi: 10.1002/bip.360350209.
We used agarose gel electrophoresis to measure the effective charge neutralization of DNA by counterions of different structure and valence, including Na+, Mg2+, Co(NH3)3+6, and spermidine3+, which competed for binding with an excess of Tris acetate buffer. Linear DNA molecules ranged in size from 1 to 5 kilobases, and supercoiled plasmid pUC18 was also measured. In all cases, the results were in good agreement with theoretical predictions from counterion condensation theory for two-counterion mixtures.
我们使用琼脂糖凝胶电泳来测量不同结构和价态的抗衡离子（包括Na⁺、Mg²⁺、Co(NH₃)₆³⁺和亚精胺³⁺）对DNA的有效电荷中和作用，这些抗衡离子与过量的醋酸 Tris 缓冲液竞争结合。线性DNA分子的大小范围为1至5千碱基，同时也测量了超螺旋质粒pUC18。在所有情况下，结果与双抗衡离子混合物的抗衡离子凝聚理论的理论预测高度一致。
