Pulling hairpinned polynucleotide chains: Does base-pair stacking interaction matter?
摘要
Force-induced structural transitions both in relatively random and in designed single-stranded DNA (ssDNA) chains are studied theoretically. At high salt conditions, ssDNA forms compacted hairpin patterns stabilized by base-pairing and base-pair stacking interactions, and a threshold external force is needed to pull the hairpinned structure into a random coiled one. The base-pair stacking interaction in the ssDNA chain makes this hairpin-coil conversion a discontinuous (first-order) phase transition process characterized by a force plateau in the force-extension curve, while lowering this potential below some critical level turns this transition into continuous (second-order) type, no matter how strong the base-pairing interaction is. The phase diagram (including hairpin-I, -II, and random coil) is discussed as a function of stacking potential and external force. These results are in quantitative agreement with recent experimental observations of different ssDNA sequences, and they reveal the necessity to consider the base-pair stacking interactions in order to understand the structural formation of RNA, a polymer designed by nature itself. The theoretical method used may be extended to study the long-range interaction along double-stranded DNA caused by the topological constraint of fixed linking number.
引用
@article{arxiv.cond-mat/0101286,
title = {Pulling hairpinned polynucleotide chains: Does base-pair stacking interaction matter?},
author = {Haijun Zhou and Yang Zhang},
journal= {arXiv preprint arXiv:cond-mat/0101286},
year = {2009}
}
备注
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