Relaxation of DNA on a supported lipid membrane

¹ Institute of Physics, Academia Sinica - Taipei, Taiwan 11529
² Department of Physics, National Central University - Jhongli, Taiwan 32001

^(b) jctsai@phys.sinica.edu.tw
^(c) wtjuan@phys.sinica.edu.tw

Received: 13 June 2012
Accepted: 30 July 2012

Abstract

We utilize real-time single-molecule imaging to investigate the transient response of DNA molecules on a rigidly supported lipid membrane upon their adsorptions. Following the stochastic landing onto the membrane at a nearly spherical initial state, these DNA coils gradually relax and expand their apparent size (R²_g,xy) in a highly anisotropic fashion. The evolution of R²_g,xy exhibits considerable variations among individual molecules, and its time dependence can be characterized by a generic exponential relaxation, but only after a statistical averaging over a large number of events. This evolution defines the primary relaxation timescale, which varies with the lipid composition of the membrane. The statistics and time-resolved analyses of the conformation of individual DNA coils further indicate that the interaction between the absorbing molecules and the lipid elements plays an important role in the relaxation towards the final equilibrium of this polymer-membrane complex.