Open AccessNuclear magnetic resonance studies of the helix-coil transition of poly (dA-dT) in aqueous solution.
Author(s) -
Dinshaw J. Patel,
Lita L. Canuel
Publication year - 1976
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.73.3.674
Subject(s) - helix (gastropod) , aqueous solution , chemistry , proton , nuclear magnetic resonance , resonance (particle physics) , crystallography , chemical shift , nuclear magnetic resonance spectroscopy , electromagnetic coil , stereochemistry , atomic physics , physics , ecology , quantum mechanics , snail , biology
The well-resolved base and sugar proton resonances in the high resolution proton nuclear magnetic resonance (NMR) spectra of poly(dA-dT) can be monitored during the helix-coil transition. The observable resonances shift upfield on helix formation and the temperature-dependent chemical shifts exhibit a melting temperature t 1/2 = 69.9 +/- 0.3 degrees for 18.8 mM (with respect to phosphorus) poly(dA-dT) in 0.5 M Tris, 0.1 M cacodylate, D2O, pH 7.05. The observable protons are in fast exchange throughout the poly (dA-dT) helix-coil transition. The adenine H2 resonance that shifts upfield by about 1 ppm on helix formation exhibits uncertainty broadening in the fast exchange region...