Relative affinities of divalent polyamines and of their N-methylated analogues for helical DNA determined by sup 23 Na NMR
- Univ. of Wisconsin, Madison (United States)
Interactions of divalent polyamines with double-helical DNA in aqueous solution are investigated by monitoring the decrease in {sup 23}Na NMR relaxation rates as NaDNA is titrated with H{sub 3}N{sup +}-(CH{sub 2}){sub m}-{sup +}NH{sup 3}, where m = 3, 4, 5, or 6. Analogous measurements are made for the same homologous series of methylated polyamines (methonium ions). The dependence of the {sup 23}Na relaxation rates on the amount of added divalent cation (M{sup 2+}) is analyzes quantitatively in terms of a two-state model. The sodium ions are assumed to be in rapid exchange between a bound state, where they are close enough to DNA so that it affects their relaxation rate, and a free state in bulk solution, where their relaxation rate is the same as in solutions containing no DNA. (1) For polyamines and methonium ions of the same m, D{sub H} exceeds D{sub Me} by factors that are significantly larger for m = 3 and 4 than for m = 5 and 6. (2) D{sub H} for m = 3 and 4 is larger than D{sub H} for m = 5 and 6. (3) D{sub Me} for m = 3 and 4 is smaller than D{sub Me} for m = 5 and 6.
- OSTI ID:
- 5077225
- Journal Information:
- Biochemistry; (United States), Vol. 30:30; ISSN 0006-2960
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
METHYLATION
DNA
NUCLEAR MAGNETIC RESONANCE
AQUEOUS SOLUTIONS
CATIONS
PROTONS
RELAXATION
SODIUM 23
ALKALI METAL ISOTOPES
BARYONS
CHARGED PARTICLES
CHEMICAL REACTIONS
DISPERSIONS
ELEMENTARY PARTICLES
FERMIONS
HADRONS
IONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MIXTURES
NUCLEI
NUCLEIC ACIDS
NUCLEONS
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
RESONANCE
SODIUM ISOTOPES
SOLUTIONS
STABLE ISOTOPES
550601* - Medicine- Unsealed Radionuclides in Diagnostics