Condensation of supercoiled DNA induced by MnCl2.
Condensation of supercoiled DNA induced by MnCl2.
复制标题
DOI：
10.1016/s0006-3495(94)80641-1
复制
发表时间：
1994-10
影响因子：
3.4
通讯作者：
Chenglie Ma;Victor A. Bloomfield
中科院分区：
文献类型：
--
作者：
Chenglie Ma;Victor A. Bloomfield
多价阳离子在体外凝聚DNA，但它一直被认为是至少+ 3价的水溶液。我们发现Mn2+可以产生超螺旋质粒DNA的环状凝聚体，但不能产生线性化质粒。Mg2+不发生缩合，MgCl2和NaCl都不能抵消MnCl2的作用，说明与Mn的缩合机制主要不是静电。超卷曲的MnDNA比线性的MnDNA更容易被S1核酸酶消化。超卷曲似乎与Mn2+合作稳定螺旋畸变，并提供“压力”，增强横向结合。
Multivalent cations condense DNA in vitro, but it had been thought that a valence of at least + 3 was required in aqueous solution. We have found that Mn2+ can produce toroidal condensates of supercoiled plasmid DNA, but not of linearized plasmid. Mg2+ does not cause condensation, and neither MgCl2 nor NaCl can negate the effect of MnCl2, indicating that the condensation mechanism with Mn is not primarily electrostatic. Supercoiled MnDNA is more extensively digested than the linear form by S1 nuclease. Supercoiling appears to cooperate with Mn2+ in stabilizing helix distortions and also provides a "pressure" that enhances lateral association.