Efficient single-strand cleavage of DNA mediated by a MnIIIMnIV-based artificial nuclease?

Dalton Transactions Pub Date: 2013-11-05 DOI: 10.1039/C3DT51904J

Abstract

A water-soluble MnIV 1,4,7-triazacyclononane complex, [MnIV2L2(μ-O)2](ClO4)2·2H2O (1), was prepared to serve as a nuclease mimic (L = 1,4,7-triazacyclononane-N-acetate). Complex 1 was readily synthesized from the highly water soluble ligand (L), with MnIII salt, [Mn3O(MeCO2)7]·3H2O in basic condition, and characterized by X-ray, IR, electronic spectroscopy, cyclic voltammetry and magnetic susceptibility as well as ESI-MS. The bond valence sum (BVS) analysis and magnetic data suggest that 1 is a MnIV–μ-O2–MnIV species. The electrospray mass spectrum and electronic spectrum of 1 in aqueous solution indicates that dinuclear Mn complex [MnIIIMnIVL2(μ-O)2]+ (2) is the active species. A predominantly hydrolytic cleavage mechanism was confirmed through experiments performed in the presence of various radical scavengers, T4 ligase and under anaerobic conditions. The kinetic aspects of DNA cleavage under pseudo- or true-Michaelis–Menten conditions were also detailed, kinetic parameters (kcat, KM, Vmax) were calculated to be 6.27 h?1, 7.35 × 10?5 M, 4.6 × 10?4 M h?1; 0.683 h?1, 1.93 × 10?5 M, 1.32 × 10?5 M h?1 for 2, respectively.

Graphical abstract: Efficient single-strand cleavage of DNA mediated by a MnIIIMnIV-based artificial nuclease
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