The recognition and catalytic hydrolysis of ATP by protonated phenanthroline-bridged polyamine and (or) Ca(II), Mg(II), Zn(II), and La(III) ions

The supramolecular interactions of 2,9-di(((2′-phenylamino)ethyleneamino)methyl)-1,10-phenanthroline (L) and (or) metal ions (M = Ca2+, Mg2+, Zn2+, or La3+) with nucleotides were investigated. Furthermore, the hydrolysis of ATP catalyzed by a protonated ligand and (or) a metal ion (M = Ca2+, Mg2+, Zn2+, or La3+) was studied at pH 7.6 using 31P NMR spectra. Kinetics studies show that at pH 7.6 the protonated ligand, with a rate constant of 2.9 × 10–4 min–1, does not significantly promote ATP hydrolysis. However, in the presence of Ca2+, Mg2+, Zn2+, or La3+ ions, L can accelerate the hydrolysis of ATP, with corresponding rate constants of 5.73, 1.48, 6.76, and 31.7 × 10–3 min–1, respectively, which are about 29-, 7.5-, 34-, and 159-fold faster than the hydrolysis rate of free ATP. By comparison with M–ATP (M = Ca2+, Mg2+, and La3+) systems, the rates of M–L–ATP were also promoted. This has been achieved through the effective recognition of ATP and the availability of a good intramolecular nucleophile, i.e., a free amino nitrogen atom of L. Compared with the Zn2+–ATP system, the decrease in the rate of the Zn2+–L–ATP system at pH 7.6 may be attributed to the competition between the mixed ligands in binding Zn2+. Similar to L–ATP, the hydrolysis reactions in the Zn2+–L–ATP or M–L–ATP (M = Ca2+, Mg2+, and La3+) systems occur through an addition–elimination type mechanism, in which phosphoramidate intermediates were observed at 2.88 and 4.06 parts per million (ppm) in the L–ATP and Mg2+–L–ATP systems, respectively. Here, metal ions add control or regulation to the hydrolysis reaction. Key words: recognition, ATP hydrolysis, metal ions, phenanthroline-bridged polyamine.