Nucleoapzymes: Hemin/G-Quadruplex DNAzyme–Aptamer Binding Site Conjugates with Superior Enzyme-like Catalytic Functions

Abstract

A novel concept to improve the catalytic functions of nucleic acids (DNAzymes) is introduced. The method involves the conjugation of a DNA recognition sequence (aptamer) to the catalytic DNAzyme, yielding a hybrid structure termed "nucleoapzyme". Concentrating the substrate within the "nucleoapzyme" leads to enhanced catalytic activity, displaying saturation kinetics. Different conjugation modes of the aptamer/DNAzyme units and the availability of different aptamer sequences for a substrate provide diverse means to design improved catalysts. This is exemplified with (i) The H2O2-mediated oxidation of dopamine to aminochrome using a series of hemin/G-quadruplex-dopamine aptamer nucleoapzymes. All nucleoapzymes reveal enhanced catalytic activities as compared to the separated DNAzyme/aptamer units, and the most active nucleoapzyme reveals a 20-fold enhanced activity. Molecular dynamics simulations provide rational assessment of the activity of the various nucleoapzymes. The hemin/G-quadruplex-aptamer nucleoapzyme also stimulates the chiroselective oxidation of L- vs D-DOPA by H2O2. (ii) The H2O2-mediated oxidation of N-hydroxy-L-arginine to L-citrulline by a series of hemin/G-quadruplex-arginine aptamer conjugated nucleoapzymes.

The Effect of Adenine Repeats on G‐quadruplex/hemin Peroxidase Mimicking DNAzyme Activity

“…Moreover,t he G-quadruplex/hemin DNAzyme system constitutes ap owerful toolkitf or use in biosensing and biomolecular devices. [48] The DNAzyme developed here facilitatest he construction of systems that can generate intense signals for other chemical processes, and furthers tudies of the aforementioned applications for G-quadruplex/ hemin with dA repeats are being undertaken in our laboratory. [44] Furthermore, there are as eries of signalp roducers that have been developed with G-quadruplex/hemin DNAzymes, such as electrocatalyzed reduction of H 2 O 2 , [45] luminol, [46] NADH, [47] and dopamine.…”

Triplex DNA Nanostructures: From Basic Properties to Applications

“…[99] For example,t he peroxidase-mimicking hemin/G-quadruplex DNAzyme was conjugated to the dopamine binding aptamer (DBA), and the 5'!3' hemin/G-quadruplex-DBAc onjugate was 20 times more active in the H 2 O 2 -mediated catalytic oxidation of dopamine to aminochrome than the separated hemin/G-quadruplex and DBAu nits.T he superior catalytic properties of the hemin/G-quadruplex-DBAc onjugate were attributed to the concentration of the dopamine substrate at the aptamer site and to the spatial positioning of the hemin/Gquadruplex close to the substrate-binding site. [99] For example,t he peroxidase-mimicking hemin/G-quadruplex DNAzyme was conjugated to the dopamine binding aptamer (DBA), and the 5'!3' hemin/G-quadruplex-DBAc onjugate was 20 times more active in the H 2 O 2 -mediated catalytic oxidation of dopamine to aminochrome than the separated hemin/G-quadruplex and DBAu nits.T he superior catalytic properties of the hemin/G-quadruplex-DBAc onjugate were attributed to the concentration of the dopamine substrate at the aptamer site and to the spatial positioning of the hemin/Gquadruplex close to the substrate-binding site.…”

Iron oxide nanozyme catalyzed synthesis of fluorescent polydopamine for light-up Zn2+detection

“…After overnight incubation at room temperature, a yellow color was developed (inset of Figure 1B), suggesting oxidation of dopamine. 1, 29 The sample was characterized by UV-vis absorption spectroscopy, and a peak centered at 450 nm was obtained ( Figure 1B, blue curve). Control samples of free dopamine, dopamine with H2O2 alone, and dopamine mixed with Fe3O4 NPs alone were also prepared.…”