INFLUENCE OF AMINO-ACIDS, AMMONIUM AND POTASSIUM CATIONS ON THE SELF-ASSEMBLY OF 5'-GMP

The self‐ordered supramolecular structures formed by 5′‐guanosine monophosphate (disodium salt) in aqueous solution at pH 7.8 show pronounced interaction with ammonium ions. Rather than competing with potassium ions for the central cavity in hydrogen‐bonded guanine tetramers, ammonium ions bring about ‐ in synergism with potassium ions ‐ further aggregation. Glycine appears to destroy the aggregates, by competing with potassium ions for the core positions within the tetramers. Conversely, alanine does not interact significantly with the system. These conclusions follow from analysis, at various concentrations, of the microdynamics and of the mole fractions of sodium ions bound to self‐assembled 5′‐GMP−−, obtained from relaxation rate measurements for the 23Na nucleus, as the 5′‐GMP−− counter‐ion. Copyright © 1979 Verlag GmbH & Co. KGaA, Weinheim