A solid-state 23Na NMR study of monovalent cation binding to double-stranded DNA at low relative humidity
Copyright (c) 2008 John Wiley & Sons, Ltd.
| Veröffentlicht in: | Magnetic resonance in chemistry : MRC. - 1985. - 46(2008), 4 vom: 15. Apr., Seite 308-15 |
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| Weitere Verfasser: | , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2008
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| Zugriff auf das übergeordnete Werk: | Magnetic resonance in chemistry : MRC |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Cations Metals, Alkali Phosphorus Isotopes Quaternary Ammonium Compounds Sodium Isotopes DNA 9007-49-2 calf thymus DNA |
| Zusammenfassung: | Copyright (c) 2008 John Wiley & Sons, Ltd. We report a solid-state (23)Na NMR study of monovalent cation (Li(+), Na(+), K(+), Rb(+), Cs(+) and NH(4) (+)) binding to double-stranded calf thymus DNA (CT DNA) at low relative humidity, ca 0-10%. Results from (23)Na--(31)P rotational echo double resonance (REDOR) NMR experiments firmly establish that, at low relative humidity, monovalent cations are directly bound to the phosphate group of CT DNA and are partially dehydrated. On the basis of solid-state (23)Na NMR titration experiments, we obtain quantitative thermodynamic parameters concerning the cation-binding affinity for the phosphate group of CT DNA. The free energy difference (DeltaG degrees ) between M(+) and Na(+) ions is as follows: Li(+) (-1.0 kcal mol(-1)), K(+) (7.2 kcal mol(-1)), NH(4) (+) (1.0 kcal mol(-1)), Rb(+) (4.5 kcal mol(-1)) and Cs(+) (1.5 kcal mol(-1)). These results suggest that, at low relative humidity, the binding affinity of monovalent cations for the phosphate group of CT DNA follows the order: Li(+) > Na(+) > NH(4) (+) > Cs(+) > Rb(+) > K(+). This sequence is drastically different from that observed for CT DNA in solution. This discrepancy is attributed to the different modes of cation binding in dry and wet states of DNA. In the wet state of DNA, cations are fully hydrated. Our results suggest that the free energy balance between direct cation-phosphate contact and dehydration interactions is important. The reported experimental results on relative ion-binding affinity for the DNA backbone may be used for testing theoretical treatment of cation-phosphate interactions in DNA |
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| Beschreibung: | Date Completed 16.04.2008 Date Revised 04.03.2008 published: Print Citation Status MEDLINE |
| ISSN: | 1097-458X |
| DOI: | 10.1002/mrc.2136 |