Hydrolysis of 5',5'-tri- or tetraphosphate-mRNA 5'-cap analogs promoted by Cu2+ or Zn2+ metal ions

The hydrolysis of 5'-CAP dinucleotide analogs: catalysis by bi- and terpyridine complexes of Cu²⁺ and Zn²⁺ ions

The kinetics of the hydrolysis of P(1)-(7-methylguanosinyl-5') P(3)-(guanosinyl-5') triphosphate (m(7)GpppG), P(1)-(7-methylguanosinyl-5') P(4)-(guanosinyl-5') tetraphosphate (m(7)GppppG), and diadenosine 5', 5'( ')-P(1),P(3) -triphosphate (ApppA) in the presence of several Cu(2+) or Zn(2+) ions complexed with bi- or terpyridine has been studied at pH 8.0 and 60 °C. Time-dependent product distributions at various metal complex concentrations have been determined by capillary zone electrophoresis and reversed-phase high performance liquid chromatography. The results show that the predominant hydrolytic reaction is the cleavage of 5',5'-oligophosphate bridge, with Cu(2+) complexes being approximately 15-fold more efficient catalysts than Zn(2+) chelates. In addition, the effect of metal ions complexes at pH 7.0 and 8.0 on the imidazole ring opening in m(7)Gua mononucleotides has been studied. The influence of Cu(2+) complexes on imidazole ring cleavage of mononucleotides is modest, whereas Zn(2+) complexes are almost inactive.