A potassium‐39 NMR study of potassium binding to double‐helical DNA

Abstract

The binding of K+ to double‐helical DNA has been examined by 39K NMR. The results obtained are in substantial agreement with previous measurements of 23Na+ binding to DNA. Thus, in both cases the fractional neutralization of DNA phosphate charge appears independent of the total univalent cation concentration. Further, the dependences of the 23Na+ and 39K + linewidths on Mg2+ and on temperature are strikingly similar. The implications of these results are discussed in terms of current theories of counterion binding to cylindrical polyelectrolytes. Copyright © 1984, Wiley Blackwell. All rights reserved