Multinuclear Quadrupolar NMR Study of Isotropic and Anisotropic Na-DNA Aqueous Solutions
Aqueous solutions of long DNA fragments with Na+ as counterion form an anisotropic phase when the DNA concentration exceeds a critical value. Various physicochemical properties of this system have been described in several studies. However, the theory of the DNA-counterion interaction in concentrated solutions is not well developed yet.
Here we present the results of a 23Na, 17O and 2 H NMR investigation of DNA concentrated aqueous solutions, ranging from 25 mg/ml to 250 mg/ml. The samples were examined at three different temperatures: 25, 35 and 45° C.
F. Cesare Marincola, M. Casu, G. Saba and A. Lai
Dipartimento di Scienze Chimiche, Universitá di Cagliari,