Binding of 5-fluorotryptamine to polynucleotides as a model for protein-nucleic acid interactions: fluorine-19 nuclear magnetic resonance, absorption, and fluorescence studies

Journal Article · Tue Feb 16 04:00:00 EST 1982 · Biochemistry; (United States)

OSTI ID:5530329

Mirau, P A; Shafer, R H; James, T L

Fluorine-19 nuclear magnetic resonance (/sup 19/F NMR), optical absorption, and fluorescence spectroscopy have been used to study the interaction of 5-fluorotryptamine (5FTA) with polynucleotides as a model for protein-nucleic acid interactions. In the presence of DNA, denatured DNA, poly(A), and poly(A)-poly(U), the /sup 19/F resonance of 5FTA shifted 0.3-0.6 ppm upfield while the presence of poly(I)-poly(C) had little effect on the chemical shift. Differences in the /sup 19/F chemical shift induced upon changing from H/sub 2/O to /sup 2/H/sub 2/O indicate difference in the solvent accesibility of 5FTA bound to the various polynucleotides. /sup 19/F NMR relaxation experiments were carried out for free 5FTA and in its nucleic acid complexes, and the results were interpreted by using a two correlation time model that included contributions to relaxation from dipolar coupling and chemical shift anisotropy. Values for the internal motion correlation time and the overall motion correlation time are reported. The effect of 5FTA on the melting transition of the double-stranded polynucleotides and on the quenching of 5FTA fluorescence was also studied. The /sup 19/F NMR results support the model of partial intercalation of the 5FTA chromophore into the polynucleotides, and the implications for protein-nucleic acid interactions are discussed.

• Research Organization: Univ. of California, San Francisco
• OSTI ID: 5530329
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 21:4; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION SPECTROSCOPY
AMINES
AZOLES
BIOLOGICAL MODELS
CHEMICAL BONDS
EMISSION SPECTROSCOPY
FLUORESCENCE SPECTROSCOPY
FLUORINE 19
FLUORINE ISOTOPES
HETEROCYCLIC COMPOUNDS
INDOLES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
NUCLEOTIDES
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRROLES
RESONANCE
SPECTROSCOPY
STABLE ISOTOPES
TRYPTAMINES