Catalysis of phosphoryl transfer from adenosine-<f>5′</f>-triphosphate (ATP) by trinuclear “chelate” complexes

The chelate ligand 2,9-di(<f>6′</f>-α-phenol-<f>n</f>-<f>2′</f>,<f>5′</f>-diazahexyl)-1,10-phenanthroline (L) was synthesized and fully characterized. This ligand formed six protonated species in the solution. The bindings of the ligand to the nucleotide anions ATP, ADP and AMP were described in detail, with equilibrium constants given for each species formed. The strength of binding increased with the number of protons, corresponding to an increase in the number of hydrogen bonds and an increase in the coulombic attractive forces. At the same time, the coordination properties of the ternary complexes formed from the chelate ligand above, M (M=Zn2+, Cd2+) and adenosine-<f>5′</f>-triphosphate (ATP) were studied. The metal complexes of the chelate recognize the nucleotides via multiple interactions similar to those occurring in the center of enzymes. The hydrolysis of ATP was studied with the mononuclear and trinuclear chelate complexes. [Copyright &y& Elsevier]