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DNA Compaction and Charge Neutralization Regulated by Divalent Ions in very Low pH Solution.

ABSTRACT: DNA conformation is strongly dependent on the valence of counterions in solution, and a valence of at least three is needed for DNA compaction. Recently, we directly demonstrated DNA compaction and its regulation, mediated by divalent cations, by lowering the pH of a solution. In the present study, we found that the critical electrophoretic mobility of DNA is promoted to around -1.0 × 10^-4 cm² V^-1 s^-1 to incur DNA compaction or condensation in a tri- and tetravalent counterions solution, corresponding to an about 89% neutralized charge fraction of DNA. This is also valid for DNA compaction by divalent counterions in a low pH solution. It is notable that the critical charge neutralization of DNA for compaction is only about 1% higher than the saturated charge fraction of DNA in a mild divalent ion solution. We also found that DNA compaction by divalent cations at low pH is weakened and even decondensed with an increasing concentration of counterions.

SUBMITTER: Gao T

PROVIDER: S-EPMC6419228 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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DNA Compaction and Charge Neutralization Regulated by Divalent Ions in very Low pH Solution.

Gao Tianyong T Zhang Wei W Wang Yanwei Y Yang Guangcan G

Polymers 20190215 2

DNA conformation is strongly dependent on the valence of counterions in solution, and a valence of at least three is needed for DNA compaction. Recently, we directly demonstrated DNA compaction and its regulation, mediated by divalent cations, by lowering the pH of a solution. In the present study, we found that the critical electrophoretic mobility of DNA is promoted to around -1.0 × 10-4 cm² V-1 s-1 to incur DNA compaction or condensation in a tri- and tetraval ...[more]

PMID: 30960321

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