CLICK-17, a DNA enzyme that harnesses ultra-low concentrations of either Cu+ or Cu2+ to catalyze the azide-alkyne 'click' reaction in water. Issue 13 (10th June 2020)

• Record Type: Journal Article
• Authors: Liu, Kun; Lat, Prince Kumar; Yu, Hua-Zhong; Sen, Dipankar
• Is Part Of: Nucleic acids research. Volume 48:Issue 13(2020)
• Page Start: 7356
• Page End: 7370
• Publication Date: 2020-06-10
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gkaa502
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: To enable the optimal, biocompatible and non-destructive application of the highly useful copper (Cu + )-mediated alkyne-azide 'click' cycloaddition in water, we have isolated and characterized a 79-nucleotide DNA enzyme or DNAzyme, 'CLICK-17', that harnesses as low as sub-micromolar Cu + ; or, surprisingly, Cu 2+ (without added reductants such as ascorbate) to catalyze conjugation between a variety of alkyne and azide substrates, including small molecules, proteins and nucleic acids. CLICK-17's Cu + catalysis is orders of magnitude faster than that of either Cu + alone or of Cu + complexed to PERMUT-17, a sequence-permuted DNA isomer of CLICK-17. With the less toxic Cu 2+, CLICK-17 attains rates comparable to Cu +, under conditions where both Cu 2+ alone and Cu 2+ complexed with a classic accelerating ligand, THPTA, are wholly inactive. Cyclic voltammetry shows that CLICK-17, unlike PERMUT-17, powerfully perturbs the Cu(II)/Cu(I) redox potential. CLICK-17 thus provides a unique, DNA-derived ligand environment for catalytic copper within its active site. As a bona fide Cu 2+ -driven enzyme, with potential for being evolved to accept only designated substrates, CLICK-17 and future variants promise the fast, safe, and substrate-specific catalysis of 'click' bioconjugations, potentially on the surfaces of living cells.