Entropic boundary effects on the elasticity of short DNA molecules.
We have measured the entropic elasticity of double-stranded-DNA molecules ranging from 247 to 1298 bp in length using axial force-clamp optical tweezers. We show that entropic end effects and excluded-volume forces from surface attachments become significant for such short molecules. The effective persistence length of the shortest molecules decreases by a factor of 2 compared to the established value for long molecules, and excluded-volume forces extend the molecules to about one third of their nominal contour length. We interpret these results in the framework of an inextensible semiflexible rod model.
Chen
Yih-Fan
YF
Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
Wilson
David P
DP
Raghunathan
Krishnan
K
Meiners
Jens-Christian
JC
D004247:DNA / Q000737:chemistry*; D004548:Elasticity; D019277:Entropy; D052898:Optical Tweezers; D013499:Surface Properties
D004247:DNA