title: Studies of the activity of peroxidase-like DNAzyme by modifying 3'- or 5'-end of aptamers.
abstract: In the presence of hemin and under appropriate conditions, some modalities of G-quadruplexes can form a peroxidase-like DNAzyme that has been widely used in biology. Structure-function studies on the DNAzyme revealed that its catalytic ability may be dependent on the unimolecular parallel G-quadruplex. In this report, we present the preliminary investigation on the relationship between the structure and function of DNAzymes through a terminal oligo modification in G-quadruplex sequences by adding different lengths of oligo-dT to the 3'- or 5'-end of the aptamers. The results suggested that adding dT(n) to the 5'-end of the DNA sequence of the enzyme improved the ability of hemin to bind with DNA, but the addition of dT(n) to the 3'-end decreased the binding ability of hemin for DNA. The increased stability of the assembled DNAzyme would lead to more favorable binding between the enzyme and substrate (H(2) O(2)), facilitating higher peroxidase activity; on the contrary, with lower stability of the DNAzyme complex, we observed reduced peroxidase activity.
authors.affiliation: College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. of China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.forename: Haiqun
authors.initials: H
authors.lastname: Li
authors.forename: Minggang
authors.initials: M
authors.lastname: Deng
authors.forename: Xiaocheng
authors.initials: X
authors.lastname: Weng
authors.forename: Heng
authors.initials: H
authors.lastname: Ma
authors.forename: Shuo
authors.initials: S
authors.lastname: Feng
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Zhou
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhou
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001483:Base Sequence; D002942:Circular Dichroism; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D054856:G-Quadruplexes; D006861:Hydrogen Peroxide / Q000378:metabolism; D007700:Kinetics; D009195:Peroxidase / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D044366:Transition Temperature
chemical_list: D052157:Aptamers, Nucleotide; D021881:DNA, Catalytic; D006861:Hydrogen Peroxide; D009195:Peroxidase