Abstract:

Highly selective recognition of metal ions by rationalligand design is challenging, and simple metal binding bybiological ligands is often obscured by nonspecific interactions.In this work, binding-triggered catalysis is used and metalselectivity is greatly increased by increasing the number ofmetal ions involved, as exemplified in a series of in vitroselected RNA-cleaving DNAzymes. The cleavage junction ismodified with a glycyl–histidine-functionalized tertiary aminemoiety to provide multiple potential metal coordination sites.DNAzymes that bind 1, 2, and 3 Zn2+ions, increased theirselectivity for Zn2+over Co2+ions from approximately 20-,1000-, to 5000-fold, respectively. This study offers importantinsights into metal recognition by combining rational liganddesign and combinatorial selection, and it provides a set of newDNAzymes with excellent selectivity for Zn2+ions.