| Literature DB >> 10978020 |
N L Goddard1, G Bonnet, O Krichevsky, A Libchaber.
Abstract
Single stranded DNA (ssDNA) equilibrium dynamics are investigated using a fluorophore/quencher-labeled hairpin structure which thermally fluctuates between open and closed states. Temporal correlations of the fluorescence fluctuations are used to determine the energy barrier to conformational change. We find that ssDNA distortion is purely entropic for poly(T) but requires an additional enthalpy of +0.5 kcal x mol(-1) x base(-1) for poly(A), consistent with the disruption of base stacking. Such sequence dependent dynamics challenge the classical model of ssDNA as a completely flexible coil.Entities:
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Year: 2000 PMID： 10978020 DOI： 10.1103/PhysRevLett.85.2400
Source DB: PubMed Journal: Phys Rev Lett ISSN： 0031-9007 Impact factor: 9.161