Force and kinetic barriers to unzipping of the DNA double helix

Simona Cocco*, Rémi Monasson, John F. Marko

*Corresponding author for this work

Research output: Contribution to journalArticle

126 Scopus citations

Abstract

A theory of the unzipping of double-stranded DNA is presented and is compared to recent micromanipulation experiments. It is shown that the interactions that stabilize the double helix and the elastic rigidity of single strands simply determine the sequence-dependent ≈ 12-pN force threshold for DNA strand separation. Using a semimicroscopic model of the binding between nucleotide strands, we show that the greater rigidity of the strands when formed into double-stranded DNA, relative to that of isolated strands, gives rise to a potential barrier to unzipping. The effects of this barrier are derived analytically. The force to keep the extremities of the molecule at a fixed distance, the kinetic rates for strand unpairing at fixed applied force, and the rupture force as a function of loading rate are calculated. The dependence of the kinetics and of the rupture force on molecule length is also analyzed.

Original languageEnglish (US)
Pages (from-to)8608-8613
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume98
Issue number15
DOIs
StatePublished - Jul 17 2001

ASJC Scopus subject areas

  • General

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