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Published on: May 19, 2014
Extension, torque, and supercoiling in single, stretched, and twisted DNA molecules
1Physics Department, Southern University, Baton Rouge, Louisiana 70813, USA.
Abstract:
We reinvestigate the model originally studied by Neukirch and Marko that describes the extension, torque, and supercoiling in single, stretched, and twisted DNA molecules, which consists of a mixture of extended state and supercoiled state, using now a more accurate form of the free energy for the untwisted but stretched DNA. The original model uses an approximate form of this free energy and the agreement with experiment is only qualitative. We find that this more accurate free energy significantly improves the results, which bring them into quantitative agreement with experiment, throughout the entire force regime. This is rather surprising, considering that the theory is completely parameter-free.
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