title: Fluorescence detection of DNA, adenosine-5'-triphosphate (ATP), and telomerase activity by zinc(II)-protoporphyrin IX/G-quadruplex labels.
abstract: The zinc(II)-protoporphyrin IX (ZnPPIX) fluorophore binds to G-quadruplexes, and this results in the enhanced fluorescence of the fluorophore. This property enabled the development of DNA sensors, aptasensors, and a sensor following telomerase activity. The DNA sensor is based on the design of a hairpin structure that includes a "caged" inactive G-quadruplex sequence. Upon opening the hairpin by the analyte DNA, the resulting fluorescence of the ZnPPIX/G-quadruplex provides the readout signal for the sensing event (detection limit 5 nM). Addition of Exonuclease III to the system allows the recycling of the analyte and its amplified analysis (detection limit, 200 pM). The association of the ZnPPIX to G-quadruplex aptamer-substrate complexes allowed the detection of adenosine-5'-triphosphate (ATP, detection limit 10 μM). Finally, the association of ZnPPIX to the G-quadruplex repeat units of telomers allowed the detection of telomerase activity originating from 380 ± 20 cancer 293T cell extract.
authors.affiliation: Institute of Chemistry, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Zhanxia
authors.initials: Z
authors.lastname: Zhang
authors.forename: Etery
authors.initials: E
authors.lastname: Sharon
authors.forename: Ronit
authors.initials: R
authors.lastname: Freeman
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.forename: Itamar
authors.initials: I
authors.lastname: Willner
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis*; D015374:Biosensing Techniques; D004247:DNA / Q000032:analysis*; D005090:Exodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism; D005453:Fluorescence; D005456:Fluorescent Dyes; D054856:G-Quadruplexes; D057809:HEK293 Cells; D006801:Humans; D057230:Limit of Detection; D011524:Protoporphyrins / Q000737:chemistry*; D019098:Telomerase / Q000032:analysis* / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D011524:Protoporphyrins; C017803:zinc protoporphyrin; D000255:Adenosine Triphosphate; D004247:DNA; D019098:Telomerase; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III