Spectroscopy study on the noncovalent interactions in the binary and ternary systems of L-lysine, adenosine 5′-triphosphate and magnesium ions

Intermolecular interactions of adenosine 5'-triphosphate (ATP) with Lysine (Lys) and Mg2+ were studied in aqueous solution by H-1 and P-31 NMR spectra. In the metal-free system, the N-1 atom of the purine ring of ATP and carboxyl group of Lys are the interaction sites at low pH conditions. With increasing pH, the interaction efficiency between the phosphate group of ATP and the protonated ammonium group of Lys increased significantly, while that with carboxyl group in Lys decreased. In the Mg2+-Lys-ATP system, multi-interactions, such as coordination, cations (Mg2+, NH3+)-pi, hydrogen bonding, ion-pairing interactions and electrostatic interactions co-existed. In addition, the recognition of ATP by the amino acid cation (Lys) was significantly promoted by the addition of magnesium ion, which led to the coordination competition between Lys and ATP. (C)2011 Elsevier B.V. All rights reserved.