Nanoconfined Circular and Linear DNA: Equilibrium Conformations and Unfolding Kinetics
Artikel i vetenskaplig tidskrift, 2015

Studies of circular DNA confined to nanofluidic channels are relevant both from a fundamental polymer-physics perspective and due to the importance of circular DNA molecules in vivo. We here observe the unfolding of confined DNA from the circular to linear configuration as a light-induced double-strand break occurs, characterize the dynamics, and compare the equilibrium conformational statistics of linear and circular configurations. This is important because it allows us to determine to what extent existing statistical theories describe the extension of confined circular DNA. We find that the ratio of the extensions of confined linear and circular DNA configurations increases as the buffer concentration decreases. The experimental results fall between theoretical predictions for the extended de Gennes regime at weaker confinement and the Odijk regime at stronger confinement. We show that it is possible to directly distinguish between circular and linear DNA molecules by measuring the emission intensity from the DNA. Finally, we determine the rate of unfolding and show that this rate is larger for more confined DNA, possibly reflecting the corresponding larger difference in entropy between the circular and linear configurations.

Författare

Mohammadreza Alizadehheidari

Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

Erik Werner

Göteborgs universitet

C. Noble

Lunds universitet

M. Reiter-Schad

Lunds universitet

Lena Nyberg

Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

Joachim Fritzsche

Chalmers, Teknisk fysik, Kemisk fysik

Bernhard Mehlig

Göteborgs universitet

J. O. Tegenfeldt

Lunds universitet

Tobias Ambjörnsson

Lunds universitet

Fredrik Persson

Uppsala universitet

Fredrik Westerlund

Kemi och kemiteknik, Kemi och biokemi, Fysikalisk kemi

Macromolecules

0024-9297 (ISSN) 1520-5835 (eISSN)

Vol. 48 871-878

Styrkeområden

Nanovetenskap och nanoteknik

Ämneskategorier

Fysik

DOI

10.1021/ma5022067