期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1976
卷号：73
期号：3
页码：674-678
DOI：10.1073/pnas.73.3.674
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：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...
