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Coarse-grained simulations of DNA overstretchingFlavio Romano, Debayan Chakraborty, Jonathan P.K. Doye, Thomas E. Ouldridge and Ard A. LouisJ. Chem. Phys. 138, 085101 (2013)AbstractWe use a recently developed coarse-grained model to simulate the overstretching of duplex DNA. Overstretching at 23oC occurs at 74pN in the model, about 6-7pN higher than the experimental value at equivalent salt conditions. Furthermore, the model reproduces the temperature dependence of the overstretching force well. The mechanism of overstretching is always force-induced melting by unpeeling from the free ends. That we never see S-DNA (overstretched duplex DNA), even though there is clear experimental evidence for this mode of overstretching under certain conditions, suggests that S-DNA is not simply an unstacked but hydrogen-bonded duplex, but instead probably has a more exotic structure.The full paper is available from The Journal of Chemical Physics and arXiv.org. |