Underwound DNA under tension: Structure, elasticity, and sequence-dependent behaviors

Maxim Y. Sheinin, Scott Forth, John F. Marko, Michelle D. Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Scopus citations


DNA melting under torsion plays an important role in a wide variety of cellular processes. In the present Letter, we have investigated DNA melting at the single-molecule level using an angular optical trap. By directly measuring force, extension, torque, and angle of DNA, we determined the structural and elastic parameters of torsionally melted DNA. Our data reveal that under moderate forces, the melted DNA assumes a left-handed structure as opposed to an open bubble conformation and is highly torsionally compliant. We have also discovered that at low forces melted DNA properties are highly dependent on DNA sequence. These results provide a more comprehensive picture of the global DNA force-torque phase diagram.

Original languageEnglish (US)
Article number108102
JournalPhysical review letters
Issue number10
StatePublished - Sep 1 2011

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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