The Alkali Ion-DNA Interaction as Reflected in the Nuclear Relaxation Rates of 23 Na and 87 Rb
- 1 January 1975
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 72 (1) , 245-247
- https://doi.org/10.1073/pnas.72.1.245
Abstract
Longitudinal relaxation rates of (23)Na and (87)Rb in aqueous solutions of DNA were measured and interpreted in terms of contributions of "bound" and free species. The frequency dependence of the (23)Na relaxation rate sets an upper limit of 5.5 nsec for the correlation time characteristic of the alkali ion-DNA interaction. The plausible description of the alkali ion-DNA interaction emerging from the results is one in which the "bound" ions comprise a highly mobile ionic cloud around the lattice of phosphate groups with a population characterized by an apparent dissociation constant of 10.9 mM. Any specific binding to phosphate groups involving severe restrictions of motional freedom must be much (at least two orders of magnitude) weaker and of a very short duration (<5.5 nsec).Keywords
This publication has 6 references indexed in Scilit:
- Effects of temperature and field strength on the NMR relaxation times of 23Na in frog striated muscleBiochimica et Biophysica Acta (BBA) - General Subjects, 1974
- DNA-Protein InteractionsAnnual Review of Biochemistry, 1972
- Nuclear magnetic resonance study of 23Na+ complexing by ionophoresBiochemistry, 1971
- 23 Na NUCLEAR MAGNETIC RESONANCE RELAXATION STUDIES OF SODIUM ION INTERACTION WITH SOLUBLE RNAProceedings of the National Academy of Sciences, 1969
- Conformation studies on the sodium and cesium salts of calf thymus deoxyribonucleic acid (DNA)Biopolymers, 1966