title: A novel potassium sensing in aqueous media with a synthetic oligonucleotide derivative. Fluorescence resonance energy transfer associated with Guanine quartet-potassium ion complex formation.
abstract: A novel potassium sensing oligonucleotide (PSO) was constructed by attaching fluorophores 6-FAM and 6-TAMRA to the 5'- and 3'-termini of d(GGG TTA GGG TTA GGG TTA GGG), respectively. The affinity of PSO for K+ was 43 000 times greater than that for Na+, high enough selectivity enabling quantitation of K+ specifically in the presence of excess Na+. Fluorescence resonance energy transfer (FRET) to 6-TAMRA from 6-FAM of PSO was observed only in the presence of K+. This phenomenon is based on the approximation of the two fluorophores upon formation of a guanine quartet mediated by K+. Furthermore, the fluorescent color of PSO changes from yellow to red upon formation of the complex, thereby enabling visualization of K+ in aqueous media.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Kyushu University, Fukuoka 812-8581, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ueyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Takagi
authors.forename: Shigeori
authors.initials: S
authors.lastname: Takenaka
mesh_terms: D001665:Binding Sites; D004735:Energy Transfer; D005452:Fluoresceins / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D009841:Oligonucleotides / Q000737:chemistry* / Q000378:metabolism; D011188:Potassium / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D012235:Rhodamines / Q000737:chemistry; D013050:Spectrometry, Fluorescence / Q000379:methods; D016615:Telomere / Q000235:genetics; D014867:Water / Q000737:chemistry
chemical_list: C106141:6-carboxytetramethylrhodamine; D005452:Fluoresceins; D005456:Fluorescent Dyes; D009841:Oligonucleotides; D012235:Rhodamines; D014867:Water; C024098:6-carboxyfluorescein; D006147:Guanine; D011188:Potassium