ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
In this paper, the effects of Na+ concentration on the overstretching transition of B-DNAmolecule at physiological temperature are studied by both experimental and numerical methods.Using optical tweezers, the relationship of external force and relative extension is obtained bystretching single B-DNA molecule at 37˚C. As the concentration increases from 0.909mM to909mM, the overstretching transition force increases from 65.65 ± 1.2pN to 43.07 ± 1.2pN. Ananalytical expression is derived, which shows that overstretching transition force is linear with thenatural logarithm of salt concentration.Based on a previous model, a three-dimensional model is proposed herein and solved byMetropolis Monte Carlo method. The bending deformation of DNA backbones, cooperativity ofbase-stacking interactions, electrostatic interactions, and spatial effects of DNA double helixstructure are taken into account. Our key contribution is that the electrostatic energy is explicitlygiven as a function of folding angle and Na+ concentration. A new parameter is also introduced toaccount for the cooperativity of base-stacking interactions. The numerical results of this model arein good agreement with our experimental results
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/23/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.121-123.1093.pdf
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