Physics – Condensed Matter – Soft Condensed Matter
Scientific paper
2006-01-16
Physics
Condensed Matter
Soft Condensed Matter
iopart, 14 pages, 13 figures, to appear in J. Phys.: Condens. Matter
Scientific paper
10.1088/0953-8984/18/14/S11
By resorting to the thick-chain model we discuss how the stretching response of a polymer is influenced by the self-avoidance entailed by its finite thickness. The characterization of the force versus extension curve for a thick chain is carried out through extensive stochastic simulations. The computational results are captured by an analytic expression that is used to fit experimental stretching measurements carried out on DNA and single-stranded RNA (poly-U) in various solutions. This strategy allows us to infer the apparent diameter of two biologically-relevant polyelectrolytes, namely DNA and poly-U, for different ionic strengths. Due to the very different degree of flexibility of the two molecules, the results provide insight into how the apparent diameter is influenced by the interplay between the (solution-dependent) Debye screening length and the polymers' ``bare'' thickness. For DNA, the electrostatic contribution to the effective radius, $\Delta$, is found to be about 5 times larger than the Debye screening length, consistently with previous theoretical predictions for highly-charged stiff rods. For the more flexible poly-U chains the electrostatic contribution to $\Delta$ is found to be significantly smaller than the Debye screening length.
Micheletti Cristian
Toan Ngo Minh
No associations
LandOfFree
Inferring the effective thickness of polyelectrolytes from stretching measurements at various ionic strengths: applications to DNA and RNA does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Inferring the effective thickness of polyelectrolytes from stretching measurements at various ionic strengths: applications to DNA and RNA, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inferring the effective thickness of polyelectrolytes from stretching measurements at various ionic strengths: applications to DNA and RNA will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-524010