Na+ shows a markedly higher potential than K+ in DNA compaction in a crowded environment
Na+ shows a markedly higher potential than K+ in DNA compaction in a crowded environment
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DOI：
10.1529/biophysj.104.057323
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发表时间：
2005-06-01
影响因子：
3.4
通讯作者：
Yoshikawa, K
中科院分区：
文献类型：
--
作者：
Zinchenko, AA;Yoshikawa, K
虽然许多物理化学研究表明，在单价阳离子Na+离子具有最小的潜力，DNA结合，生物测定表明，Na+离子（与K+离子）在染色质压实和相关过程中发挥主要作用。很难解释Na+和K+的压实势与它们的结合能力之间的这种反比关系。在这项研究中，我们试图解决这一矛盾，并强调DNA压缩和DNA结合过程的情况下，由一价阳离子的DNA压缩的现象学区别。使用聚乙二醇溶液作为拥挤的细胞环境的模型，我们研究了碱金属盐LiCl，NaCl，KCl，RbCl和CsCl的DNA压缩，并发现所有这些单价阳离子促进DNA压缩。在这些单价阳离子中，Na+产生最大的压缩，K+ c和Na+浓度的比率为1.5-2。最近的实验结果的比较分析表明，较高的一价阳离子的结合活性通常对应于相应的一价离子的低压实电位。这种反比关系被解释为在紧凑的状态下的一价阳离子的部分脱水的结果。
Whereas many physicochemical investigations have shown that among monovalent cations Na+ ion possesses minimal potential for DNA binding, biological assays have shown that Na+ ion ( in contrast to K+ ion) plays a primary role in chromatin compaction and related processes. It is difficult to explain this inverse relationship between the compaction potentials of Na+ and K+ and their binding abilities. In this study we sought to resolve this contradiction and emphasize the phenomenological distinction between DNA compaction and DNA binding processes in the case of DNA compaction by monocations. Using polyethylene glycol solutions as a model of a crowded cell environment, we studied DNA compaction by alkali metal salts LiCl, NaCl, KCl, RbCl, and CsCl, and found that all of these monocations promote DNA compaction. Among these monovalent cations Na+ produces the greatest compaction and the ratio of K+ cand Na+ oncentrations for DNA compaction is similar to 1.5-2. A comparative analysis of recent experimental results indicates that a higher binding activity of monocation generally corresponds to a low compaction potential of the corresponding monovalent ion. This inverse relation is explained as a result of partial dehydration of monocations in the compact state.