Change search
ReferencesLink to record
Permanent link

Direct link
There and (slowly) back again: entropy-driven hysteresis in a model of DNA overstretching
Univ Calif Berkeley, Dept Chem, Berkeley.
2008 (English)In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 94, no 7, 2452-2469 p.Article in journal (Refereed) Published
Abstract [en]

When pulled along its axis, double-stranded DNA elongates abruptly at a force of similar to 65 pN. Two physical pictures have been developed to describe this overstretched state. The first proposes that strong forces induce a phase transition to a molten state consisting of unhybridized single strands. The second picture introduces an elongated hybridized phase called S-DNA. Little thermodynamic evidence exists to discriminate directly between these competing pictures. Here we show that within a microscopic model of DNA we can distinguish between the dynamics associated with each. In experiment, considerable hysteresis in a cycle of stretching and shortening develops as temperature is increased. Since there are few possible causes of hysteresis in a system whose extent is appreciable in only one dimension, such behavior offers a discriminating test of the two pictures of overstretching. Most experiments are performed upon nicked DNA, permitting the detachment (unpeeling) of strands. We show that the long-wavelength progression of the unpeeled front generates hysteresis, the character of which agrees with experiment only if we assume the existence of S-DNA. We also show that internal melting can generate hysteresis, the degree of which depends upon the nonextensive loop entropy of single-stranded DNA.

Place, publisher, year, edition, pages
2008. Vol. 94, no 7, 2452-2469 p.
National Category
URN: urn:nbn:se:kth:diva-79153DOI: 10.1529/biophysj.107.117036ISI: 000254076300007OAI: diva2:495170
QC 20120209Available from: 2012-02-08 Created: 2012-02-08 Last updated: 2012-02-09Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Pronk, Sander
In the same journal
Biophysical Journal

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 18 hits
ReferencesLink to record
Permanent link

Direct link