Weakly bound water molecules shorten single-stranded DNA
| Autor: | Hermann E. Gaub, Christian Albrecht, Shuxun Cui, Ferdinand Kühner |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Ab initio
DNA Single-Stranded 1-Propanol Microscopy Atomic Force Biochemistry Oligomer Catalysis symbols.namesake chemistry.chemical_compound Colloid and Surface Chemistry Computational chemistry Benzene Derivatives Molecule Bound water Physics::Chemical Physics Elasticity (economics) Guanidine Quantitative Biology::Biomolecules Aqueous solution Chemistry Force spectroscopy Water Hydrogen Bonding General Chemistry Elasticity Chemical physics symbols Solvents Quantum Theory van der Waals force |
| Zdroj: | Journal of the American Chemical Society. 128(20) |
| ISSN: | 0002-7863 |
| Popis: | In this paper, we measure the single chain elasticity of an oligomer single-stranded DNA (ssDNA) in both aqueous and nonaqueous, apolar liquid environments by AFM-based single molecule force spectroscopy. We find a marked deviation between the force-extension relations recorded for the two conditions. This difference is attributed to the additional energy required to break the H-bond-directed water bridges around the ssDNA chain in aqueous solutions, which are nonexistent in organic solvents. The results obtained in 8 M guanidine-HCl solution provide more evidence that water bridges around ssDNA originate the observed deviation. On the basis of the results obtained by an ab initio quantum mechanics calculation, a parameter-free freely rotating chain model is proposed. We find that this model is in perfect agreement with the experimental force-extension curve obtained in organic solvents, which further corroborates our assumption. On the basis of the experimental results, it is suggested that the weak H-bonding between ssDNA and water molecules may be a precondition for stable double-stranded DNA to exist in water. |
| Databáze: | OpenAIRE |
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