2024/10/30 by Midas Segers, Enrico Skoruppa, Segers, Midas +5 · 1 citation
Biochemistry, Genetics and Molecular Biology · Chemistry · #Advanced biosensing and bioanalysis techniques #Biomolecules (q-bio.BM) #DNA and Nucleic Acid Chemistry #Electrostatics and Colloid Interactions #FOS: Biological sciences #FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft) #Statistical Mechanics (cond-mat.stat-mech)
paper · pdf · doi:10.48550/arxiv.2410.23145
openalex publication_date 2024/10/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A stretched DNA molecule which is also under- or overwound, undergoes a buckling transition forming intertwined looped domains called plectonemes. Here we develop a simple theory that extends the two-phase model of stretched supercoiled DNA, allowing for the coexistence of multiple plectonemic domains by including positional and length distribution entropies. Such a multiplectoneme phase is favored in long DNA molecules in which the gain of positional entropy compensates for the cost of nucleating a plectoneme along a stretched DNA segment. Despite its simplicity, the developed theory is shown to be in excellent agreement with Monte Carlo simulations of the twistable wormlike chain model. The theory predicts more plectonemes than experimentally observed, which we attribute to the limited resolution of experimental data. Since plectonemes are detected through fluorescence signals, those shorter than the observable threshold are likely missed.