title: Phosphorescent sensor for phosphorylated peptides based on an iridium complex.
abstract: A bis[(4,6-difluorophenyl)pyridinato-N,C(2')]iridium(III) picolinate (FIrpic) derivative coupled with bis(Zn(2+)-dipicolylamine) (ZnDPA) was developed as a sensor (1) for phosphorylated peptides, which are related to many cellular mechanisms. As a control, a fluorescent sensor (2) based on anthracene coupled to ZnDPA was also prepared. When the total negative charge on the phosphorylated peptides was changed to -2, -4, and -6, the emission intensity of sensor 1 gradually increased by factors of up to 7, 11, and 16, respectively. In contrast, there was little change in the emission intensity of sensor 1 upon the addition of a neutral phosphorylated peptide, non-phosphorylated peptides, or various anions such as CO3(2-), NO3(-), SO4(2-), phosphate, azide, and pyrophosphate. Furthermore, sensor 1 could be used to visually discriminate between phosphorylated peptides and adenosine triphosphate in aqueous solution under a UV-vis lamp, unlike fluorescent sensor 2. This enhanced luminance of phosphorescent sensor 1 upon binding to a phosphorylated peptide is attributed to a reduction in the repulsion between the Zn(2+) ions due to the phenoxy anion, its strong metal-to-ligand charge transfer character, and a reduction in self-quenching.
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University , Seoul 151-747, South Korea.
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Kang
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Tae-Hyuk
authors.initials: TH
authors.lastname: Kwon
authors.forename: Jong-In
authors.initials: JI
authors.lastname: Hong
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D007477:Ions / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D010848:Picolinic Acids / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D005456:Fluorescent Dyes; D007477:Ions; D008024:Ligands; D010455:Peptides; D010848:Picolinic Acids; C000593319:bis((4,6-difluorophenyl)pyridinato-N,C(2'))iridium(III)picolinate; D007495:Iridium; D000255:Adenosine Triphosphate; C030614:picolinic acid