Insights into the binding of arginine to adenosine phosphate from mimetic complexes

The amino acid arginine plays a key role in the interaction of proteins with adenosine phosphates, as its protonated guanidinium side group is capable of building multipodal H-bonding interactions with the oxygen atoms of the phosphate, phosphoester and ribose moieties and with the nitrogen atoms of adenine. Protein interactions often take place in competition with other ionic species, typically metal cations, which are prone to build concerted coordination arrangements with the same centers of negative charge as guanidinium. We report on a vibrational spectroscopy and computational investigation of a positively charged ternary complex formed by adenosine monophosphate (AMP) with methyl guanidinium and Na