title: The Effect of Adenine Repeats on G-quadruplex/hemin Peroxidase Mimicking DNAzyme Activity.
abstract: The catalytic activity of G-quadruplex/hemin is much lower than that of proteinous enzymes, so it is very important to increase its activity. Very recently, flanking sequences, which can be regarded as an external part of G-quadruplexes, were found to enhance the activity of G-quadruplex/hemin DNAzyme. However, little is known about the effect of internal parts, such as loop sequences and linkers, on the activity. In the present study, adenine repeats were incorporated into several designed G-quadruplex structures either in the loops, bulges, or linkers, and the constructed G-quadruplex/hemin DNAzyme exhibit about fivefold improvement in peroxidase-mimicking activity in some cases. The enhancement effect may result from the formation of compound I, protoporphyrin⋅FeIV=O.+, accelerated by dA repeats, which was demonstrated by H2O2decay kinetics and pH dependency analysis. The novel enhancement methods described here may help in the development of high-activity DNAzymes, illustrated by a dimer G-quadruplex with flanking adenine at one end, a relatively long adenine run in one loop, and another adenine run in the linker.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
authors.forename: Jielin
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
authors.forename: Yuehua
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China.
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D000225:Adenine / Q000737:chemistry*; D001483:Base Sequence; D002942:Circular Dichroism / Q000379:methods; D021881:DNA, Catalytic / Q000737:chemistry*; D054856:G-Quadruplexes; D006427:Hemin / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D010544:Peroxidases / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D021881:DNA, Catalytic; D006427:Hemin; D010544:Peroxidases; D000225:Adenine
keywords: DNA structures; DNAzyme; peroxides; pi interactions; porphyrinoids