Competitive Na+ and Rb+ binding in the minor groove of DNA
Sequence-dependent coordination of alkali ions to the nucleotide bases in the minor groove of AT-tract B-DNA has recently been inferred from X-ray crystallography, solution NMR and computer simulations. Here, we present new Na-23 and Rb-87 magnetic relaxation dispersion (MRD) data that demonstrate competitive and long-lived binding of Na+ and Rb+ ions in the minor groove of the B-DNA duplex [d(CGC
