Transition on the entropic elasticity of DNA induced by intercalating molecules
Abstract
We use optical tweezers to perform stretching experiments on DNA molecules when interacting with the drugs daunomycin and ethidium bromide, which intercalate the DNA molecule. These experiments are performed in the low-force regime from zero up to 2 pN. Our results show that the persistence length of the DNA-drug complexes increases strongly as the drug concentration increases up to some critical value. Above this critical value, the persistence length decreases abruptly and remains practically constant for larger drug concentrations. The contour length of the molecules increases monotonically and saturates as drugs concentration increases. Measured in- tercalants critical concentrations for the persistence length transition coincide with reported values for the helix-coil transition of DNA-drug complexes, obtained from sedimentation experiments.
Keywords
Cite
@article{arxiv.0704.2346,
title = {Transition on the entropic elasticity of DNA induced by intercalating molecules},
author = {M. S. Rocha and M. C. Ferreira and O. N. Mesquita},
journal= {arXiv preprint arXiv:0704.2346},
year = {2009}
}
Comments
This experimental article shows and discuss a transition observed in the persistence length of DNA molecules when studied as a function of some intercalating drug concentrations, like daunomycin and ethidium bromide. It has 15 pages and 4 figures. The article presented here is in preprint format