文章基本信息

标题：Chromatin compaction under mixed salt conditions: Opposite effects of sodium and potassium ions on nucleosome array folding
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作者：Abdollah Allahverdi ; Qinming Chen ; Nikolay Korolev 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep08512
语种：English
出版社：Springer Nature
摘要：It is well known that chromatin structure is highly sensitive to the ionic environment. However, the combined effects of a physiologically relevant mixed ionic environment of K⁺, Mg²⁺ and Na⁺, which are the main cations of the cell cytoplasm, has not been systematically investigated. We studied folding and self-association (aggregation) of recombinant 12-mer nucleosome arrays with 177 bp DNA repeat length in solutions of mixtures of K⁺ and Mg²⁺ or Na⁺ and Mg²⁺. In the presence of Mg²⁺, the addition of sodium ions promotes folding of array into 30-nm fibres, whereas in mixtures of K⁺ and Mg²⁺, potassium ions abrogate folding. We found that self-association of nucleosome arrays in mixed salt solutions is synergistically promoted by Mg²⁺ and monovalent ions, with sodium being slightly more efficient than potassium in amplifying the self-association. The results highlight the importance of a mixed ionic environment for the compaction of chromatin under physiological conditions and demonstrate the complicated nature of the various factors that determine and regulate chromatin compaction in vivo .