Pd(gly-L-his-L-lys)Cl: solution structure and ternary complex formation with mono-and tetranucleotides

The tripeptide complex Pd(gly-L-his-L-lys)Cl (Pd(GHK)Cl, 1) has been studied by a variety of NMR techniques (H-1, H-1 E.COSY, H-1 NOESY, H-1,C-13 HMQC), by ESI-MS, as well as simulated annealing and molecular dynamics methods. Reactions of 1 with isolated 5'-deoxynucleotides of guanine, cytidine, adenine and thymine, alone and in competition, have been carried out in water and followed by H-1 NMR spectroscopy. They reveal preferential binding of Pd(GHK)(+) to guanine N7 in weakly to moderately acidic solution and slow rotation of the Pd tripeptide entity about the metal-N7 bond below 276 K. The self-complementary tetranucleotide 5'-d(GTAC) reacts with 1 in D2O, pD 3.5, at guanine N7. (C) 1998 Elsevier Science S.A. All rights reserved.