Catalysis of DNA cleavage by lanthanide complexes with nucleophilic or intercalating ligands and their kinetic characterization

Abstract

The catalysis of plasmid ds-DNA cleavage by lanthanoid cations and their complexes is characterized by saturation kinetics; addition of polyamines or cryptand does not hinder catalysis, which can be enhanced to a total factor of 107 by alcoholic co-substrates such as glycerol, or by intercalating ligands.The hydrolytic cleavage of nucleic acids by lanthanides' is of considerable interest, in particular for possible biotechnological applications. The extremely long half-life time of DNA approaching more than 100 million years for total hydrolysis* makes the development of supramolecular catalysts a particular challenge. With few exceptions,3 the up to date available chemical nucleases cleave DNA by radical processes$ with the disadvantage of less discriminate reactions of e.g. highly reactive hydroxy radicals, and of concomitant partial destruc-Ln3+:

A tris-phenylphenol N8O3 Schiff-base cryptand: structural characterization and fluorescence titration for lanthanide coordination

“…A coordination proton transfer may be described by the following equations, where S represents solvent acetonitrile or water coming from the hydrate lanthanide perchlorates: 16 . Like the other sodium cryptates of the N 8 O 3 Schiffbase cryptands reported previously, 11,12 1 presents broad overlapped NMR spectra in DMSO-d 6 (or in CD 3 CN or CDCl 3 ) at room temperature, possibly resulting from the conformational mobility or multiple-proton transfer in the cavity. Owing to the low solubility, it seems that the Schiff-base compound is difficult to use in further NMR studies.…”

“…4,5 Recently, lanthanide complexes have been used as catalysts for the hydrolysis of phosphodiesters and of DNA. [6][7][8] We have reported the use of lanthanide complexes to scavenge superoxide radicals. 9 To form more stable lanthanide complexes for further potential use, the design and syntheses of macrocyclic lanthanide complexes are currently attracting much attention.…”

Gel-Electrophoresis and Its Applications

“…From these curve fits, the DNA hydrolysis rates were determined as 0.91 h -1 (R=0.971), 0.79 h -1 (R=0.971), 1.35 h -1 (R=0.983), 0.56h -1 (R=0.959), 1.32 h -1 (R = 0.971), 1.40 h -1 (R = 0.971 ), 1.74 h -1 (R=0.985), 0.65h -1 (R=0.963) for 1-8 respectively. The enhancement of DNA hydrolysis rate constant by metal complexes in the range of 0.09-0.25 h -1 was considered impressive (Rammo, J. et al, 1996., Roigk, A.; Hettich, R.; Schneider, H. J.; 1998). The above rate constants of the complexes (1-8) amounts to (1.5 -4.6) x10 7 h -1 fold rate enhancement compared to uncatalyzed double stranded DNA (3.6 x 10 -8 h -1 ) (Sreedhra, A.;Freed, J. D.;Cowan, J.…”

Compostos fosfatados ricos em energia

“…Acelerações grandes de velocidade foram obtidas, particularmente com íons Co 3+ coordenados [88][89][90] . Diversos exemplos recentes podem ainda ser encontrados na literatura para a hidrólise de fosfodiésteres mediada por íons metálicos [91][92][93][94][95][96][97][98] .…”