title: Cationic Peptide Conjugation Enhances the Activity of Peroxidase-Mimicking DNAzymes.
abstract: Peroxidase-mimicking DNAzymes containing G-quadruplex structures are widely applied in chemistry as catalysts and signal amplification for biosensing. Enhancing the catalytic activity of these DNAzymes can therefore improve the performance of many catalysts and biosensors using them. In this work, we synthesized cationic peptide conjugates of peroxidase-mimicking DNAzymes, which were found to exhibit both enhanced peroxidase and oxidase activities up to 4-fold and 3-fold compared with the original DNAzymes, respectively. Further investigation suggested that the enhanced activity was ascribed to the stabilization of parallel DNA G-quadruplex structures and hemin binding by the cationic peptide covalently attached to the DNAzyme. Such a mechanism of activity enhancement was successfully utilized for biosensing applications with improved sensitivity and broadened target range. Hydrogen peroxide (H2O2) detection in K(+)-free solutions by the DNAzyme-peptide conjugate showed 2-fold sensitivity enhancement over the unmodified DNAzyme under the same condition, and the activity switch by target-induced cleavage of the DNAzyme-peptide conjugate was also used for the detection of caspase 3 protease with enzymatic amplification in homogeneous solutions.
authors.affiliation: Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University , Beijing 100084, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Beijing Third Class Tobacco Supervision Station , Beijing 101121, China.
authors.forename: Zhaojuan
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University , Beijing 100084, China.
authors.forename: Mengli
authors.initials: M
authors.lastname: Feng
authors.affiliation: Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University , Beijing 100084, China.
authors.forename: Aijun
authors.initials: A
authors.lastname: Tong
authors.affiliation: Department of Chemistry, Beijing Key Laboratory for Microanalytical Methods and Instrumentation, Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Tsinghua University , Beijing 100084, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiang
mesh_terms: D002412:Cations; D002942:Circular Dichroism; D021881:DNA, Catalytic / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry*; D010544:Peroxidases / Q000378:metabolism*
chemical_list: D002412:Cations; D021881:DNA, Catalytic; D010455:Peptides; D010544:Peroxidases