A NanoBRET® tracer is composed of a bioavailable small molecule ligand or inhibitor of a target protein that is covalently conjugated to a fluorescent dye. Several NanoBRET® tracers were developed as a part of the NanoBRET® TE Intracellular Kinase Assay system, which uses a bioluminescent resonance energy transfer (BRET)-based method to measure compound binding at select target kinases within intact cells.
Specifically, the NanoBRET® TE Kinase assays enable the analysis of cellular apparent affinity of test compounds by competitive displacement of a cell-permeable NanoBRET® tracer reversibly bound to a kinase-NanoLuc® luciferase fusion protein in cells. The kinase-NanoLuc® fusion protein serves as the energy donor, while the fluorescent NanoBRET® TE Tracer serves as the energy acceptor in the BRET assay.
The NanoBRET® TE Tracers can be purchased individually or as part of a NanoBRET® TE Intracellular Kinase Assay. Each NanoBRET® TE Kinase Assay provides the reagents needed for NanoBRET® detection, including a NanoBRET® Tracer, NanoBRET® Nano-Glo® Substrate, Extracellular NanoLuc® Inhibitor and Tracer Dilution Buffer. The NanoBRET® TE Tracers provide users with increased flexibility to study new kinases or test alternate tracers.
Specific kinase-NanoLuc® fusion vectors are available separately. A recommended NanoBRET® tracer and concentration for a selected kinase-NanoLuc® fusion protein can be found in an application note here.