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The pulling force of a single DNA molecule condensed by spermidine

R. Zhang·B. I. Shklovskii
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Abstract

In a recent experiment, a single DNA double helix is stretched and relaxed in the presence of spermidine, a short positive polyelectrolyte, and the pulling force is measured as a function of DNA extension. In a certain range of spermidine concentration, a force plateau appears whose value shows maximum as a function of spermidine concentration. We present a quantitative theory of this plateau force based on the theory of reentrant condensation and derive almost parabolic behavior of the plateau force as a function of the logarithm of the spermidine concentration in the range of condensation. Our result is in good agreement with experimental data.

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R. Zhang, B. I. Shklovskii. 2004-01-09. The pulling force of a single DNA molecule condensed by spermidine. https://doi.org/10.1016/j.physa.2004.11.013

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