Zippered G-quadruplex/hemin DNAzyme: exceptional catalyst for universal bioanalytical applications

Abstract

G-quadruplex (G4)/hemin DNAzyme is promising horseradish peroxidase (HRP)-mimic candidate in the biological field. However, its relatively unsatisfactory catalytic capacity limits the potential applications. Inspired by nature protease, we conducted a proximity-enhanced cofactor assembly strategy (PECA) to form an exceptional HRP mimic, namely zippered G4/hemin DNAzyme (Z-G4/H). The hybridization of short oligonucleotides induced proximity assembly of the DNA-grafted hemin (DGH) with the complementary G4 sequences (cG4s), mimicking the tight configuration of protease cofactor and apoenzyme. The detailed investigations of catalytic efficiency and mechanism verified the higher activity, more rapid catalytic rate and high environmental tolerance of the Z-G4/H than the classical G4/hemin DNAzymes (C-G4/H). Furthermore, a proximity recognition transducer has been developed based on the PECA for sensitive detection of gene rearrangement and imaging human epidermal growth factor receptor 2 protein (HER2) dimerization on cell surfaces. Our studies demonstrate the high efficiency of Z-G4/H and its universal application potential in clinical diagnostics and biomolecule interaction research. It also may offer significant opportunities and inspiration for the engineering of the protease-free mimic enzyme.

Framework and Spherical Nucleic Acids Synergistically Enhanced Electrochemiluminescence Nanosensors for Rapidly Diagnosing Acute Myocardial Infarction Based on Circulating MicroRNA Levels

“…Design and Characterization of ECL Nanosensor for miRNA Detection. The c-SNAzyme is fabricated based on a hemin-conjugated strand 30 and SNA. As shown in Figure 1A, citrate-stabilized AuNPs are modified with thiolated probe A and a G4 sequence at a ratio of 1:2.…”

“…In this work, we adopt conjugated SNAzymes (c-SNAzymes), in which hemin is covalently linked to DNAs, − to avoid the above trouble. Two probe strands are tethered to c-SNAzymes and the FNA nanoplatform, respectively, and directly hybridized with target miRNAs to form a Y-shaped junction.…”

Dancing in local space: rolling hoop orbital amplification combined with local cascade nanozyme catalytic system to achieve ultra-sensitive detection of exosomal miRNA

“…As reported in previous studies, both Fe-Zr MOF and G4 have the peroxidase-like activity. In addition, our research group has also explored the catalytic performance of different G4 nanozyme structures in previous reports [ 35 , 42 , 51 ]. In this study, we also verified the catalytic capabilities of different G4 structures (Additional file 1 : Fig.…”

“…With the addition of the target exo-miRNA, the pried circular DNA enzyme achieves localized targeted rolling cleavage through a foothold-mediated strand substitution reaction, thereby releasing the signal probe for efficient and orderly signal amplification. On the surface of ECL electrode, Fe-Zr MOF/G4 nanozyme with peroxidase activity [ 41 , 42 ] and Cu 2 O/Au with glucose oxidase activity [ 43 , 44 ] form a cascade catalytic reaction in a local space through the signal probe. In the presence of low-dose glucose, the cascade nanozyme system can catalyze luminol immobilized in Fe-Zr MOF to produce a high ECL signal.…”

A Washing-Free and Easy-to-Operate Fluorescent Biosensor for Highly Efficient Detection of Breast Cancer-Derived Exosomes

“…Traditional fluorescence detection methods mostly use ready-made peroxidases such as HRP ( Lu and Xu, 2019 ; Heo et al, 2021 ) and ALP ( Han et al, 2020 ; Wu et al, 2022 ) to catalyze the substrate such as tyramine ( Zhang et al, 2020a ; Kang et al, 2020 ) and thioflavin T ( Wu et al, 2018 ; Pramanik et al, 2021 ) to output fluorescent signals. The disadvantages of this method lie in that the enzyme protein is relatively unstable and has harsh requirements on reaction conditions, which make researchers turn their attention to the G4-hemin biomimetic enzyme ( Li et al, 2021a ; Huang et al, 2021 ). The advantages of G4-hemin are excellent catalytic performance, high structural flexibility and stability ( Cao et al, 2020 ; Chen et al, 2020 ).…”