Supramolecular chemistry. Part 71.1 Evidence for hydrolytic DNA cleavage by lanthanide(III) and cobalt(III) derivatives

Abstract

Double stranded plasmidic DNA, cleaved by either europium(III) salts or by the cobalt(III)–cyclen complex, is religated for the first time without the use of enzymes, showing hydrolytic mechanisms with these chemical nucleases. The same result is observed in the hydrolysis of the dinucleotide TpT by Eu^III, which is achieved in 25% conversion. The only products observed by HPLC are 3′,5′-cTMP, 3′-TMP, 5′-TMP and thymidine. The nucleobase thymine itself is not detected (<1%), which demonstrates the absence of radical cleavage. The dinucleotide hydrolysis shows, with [Eu^III] = 5 mM, rate enhancement factors of >10⁷, which even exceed those observed with activated phenyl phosphates.