title: Characterization of the G-quadruplex structure of a catalytic DNA with peroxidase activity.
abstract: It has been reported that the complexes formed by hemin and some G-quadruplexes can be developed as a new class of DNAzyme with peroxidase activity. This kind of DNAzyme has received a great deal of attention. But to date, the actual G-quadruplex structure that can provide hemin with enhanced peroxidase activity is in doubt. Herein, the G-quadruplex structure of CatG4, a 21-nucleotide DNA oligomer which was previously reported to bind hemin and the resulting complex exhibiting enhanced peroxidase activity, was characterized by fluorescence and circular dichroism measurements. The results suggest that the catalytically active form of CatG4 may be a unimolecular parallel quadruplex rather than a unimolecular chair-type antiparallel quadruplex or a multistranded parallel quadruplex. In addition, the fluorescence analysis of labeled oligonucleotides may be developed as a supplementary tool for the study of DNA conformations.
authors.affiliation: Key Laboratory of Functional Polymer Materials (Nankai University), Ministry of Education, Department of Chemistry, Research Centre for Analytical Sciences, Nankai University, Tianjin 300071, People's Republic of China. kongdem@nankai.edu.cn
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Kong
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Cai
authors.forename: Jun-Hong
authors.initials: JH
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Wu
authors.forename: Han-Xi
authors.initials: HX
authors.lastname: Shen
mesh_terms: D002384:Catalysis; D002942:Circular Dichroism; D021881:DNA, Catalytic / Q000737:chemistry* / Q000378:metabolism*; D005453:Fluorescence; D054856:G-Quadruplexes; D006427:Hemin / Q000378:metabolism; D007477:Ions; D009691:Nucleic Acid Denaturation; D009841:Oligonucleotides / Q000737:chemistry; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism*; D012235:Rhodamines / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet
chemical_list: C114557:5-carboxytetramethylrhodamine succinimidyl ester; D021881:DNA, Catalytic; D007477:Ions; D009841:Oligonucleotides; D012235:Rhodamines; D006427:Hemin; D010544:Peroxidases