title: Homogeneous detection of avidin based on switchable lanthanide luminescence.
abstract: We have developed switchable lanthanide luminescence-based binary probe technology for homogeneous detection of avidin, which is a tetrameric protein. Two different nonluminescent label moieties--a light-absorbing antenna ligand and a lanthanide ion carrier chelate--were conjugated to separate biotins, which is known as avidin's natural ligand. The assay was based on binding of the two differently labeled biotins on separate binding sites on the target protein and consequent self-assembly of a luminescent complex from the two label moieties. Specific luminescence signal was observed only at the presence of the target protein. The characteristics of the switchable lanthanide luminescence assay were compared to the reference assay, based on lanthanide resonance energy transfer. Both assays had a limit of detection in the low-picomolar concentration range; however, the lanthanide chelate complementation-based assay had wider dynamic range and its optimization was more straightforward. The switchable lanthanide luminescence technology could be further applied to generic protein detection, using reagents that are analogous to the proximity ligation assay principle.
authors: Department of Biotechnology, University of Turku, Tykistökatu 6 A, Sixth Floor, FI-20520 Turku, Finland. umskar@utu.fi
authors: Ulla
authors: U
authors: Karhunen
authors: Jaana
authors: J
authors: Rosenberg
authors: Urpo
authors: U
authors: Lamminmäki
authors: Tero
authors: T
authors: Soukka
mesh_terms: D001360:Avidin / Q000032:analysis*; D001665:Binding Sites; D001710:Biotin / Q000737:chemistry / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008163:Luminescent Measurements
chemical_list: D028581:Lanthanoid Series Elements; D001360:Avidin; D001710:Biotin