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TR-FRET and FP Assay Reagents

TR-FRET (Time-Resolved Fluorescence Resonance Energy Transfer) and FP (Fluorescence Polarization) assays are widely used in biology and drug discovery to study target engagement. Bio-Techne offers a range of fluorescent probes suitable for the development of TR-FRET and FP assays.

Products

Product Name  Catalog # Action
BDY FL Lenalidomide 7857 Fluorescent cereblon ligand
BDY FL Staurosporine 7985 Fluorescent probe targeting kinases; kinase tracer for TR-FRET assays
BDY FL Thalidomide 7633 High-affinity fluorescent cereblon probe for use in TR-FRET assays
BDY FL VH032 7483 High-affinity VHL fluorescent probe for TR-FRET and FP assays
CELT-133 7952 Selective hα1A adrenergic receptor fluorescent antagonist
CELT-211 7953 Fluorescent serotonin 5HT2B receptor ligand for HTS; suitable for use in TR-FRET
CELT-327 7954 Potent and selective hA2B/A3 adenosine receptor fluorescent antagonist
CELT-426 7955 Potent and partially selective hD2 dopamine receptor fluorescent antagonist
CoraFluor™ 1, amine reactive 7920

Terbium cryptate FRET donor for TR-FRET assay development; amine reactive for conjugation; λabs = 337 nm

CoraFluor™ 2, amine reactive 7950

Terbium cryptate FRET donor for TR-FRET assay development; amine reactive for conjugation; λabs = 365/405 nm

FAM-DEALA-Hyp-YIPD 7287 Fluorescent HIF-1α peptide; can be used to assess VHL binding in FP assays
FAM-DEALAHypYIPMDDDFQLRSF 7452 Fluorescent HIF-1α peptide; can be used to assess VHL binding in FP assays
FITC-labelled Keap1-Nrf2 probe 7627 Fluorescent Keap1-Nrf2 peptide for use in TR-FRET and FP assays
Fluorescein-NAD+ 6574 Fluorescent NAD+; substrate for ADP-ribosylation for use in PARP assays; wavelength compatible with use as an acceptor dye in TR-FRET assays
JQ1-FITC 7722 Fluorescent BET bromodomain probe; suitable for use in TR-FRET
LDV FITC 4577 Fluorescent α4β1 integrin ligand; wavelength compatible with use as an acceptor dye in TR-FRET assays
PARPi-FL 6461 Fluorescent potent PARP inhibitor; wavelength compatible with use as an acceptor dye in TR-FRET assays
Thalidomide-Cyanine 5 7288 High affinity cereblon fluorescent probe for use in TR-FRET
Tocrifluor T1117 2540 Fluorescent cannabinoid CB1 receptor ligand; wavelength compatible with use as an acceptor dye in TR-FRET assays

Product Feature: CoraFluor Probes for TR-FRET

CoraFluor™ 1, amine reactive (Catalog # 7920) and CoraFluor™ 2, amine reactive (Catalog # 7950) are terbium-based probes that have been developed for use as TR-FRET donors. They emit wavelengths compatible with commonly used fluorescent acceptor dyes such as BODIPY® (or BDY) and Janelia Fluor® dyes, FITC (Catalog # 5440), TMR and Cyanine 5 (Catalog # 5436). CoraFluor fluorescence is brighter and more stable in biological media than existing TR-FRET donors, leading to enhanced sensitivity and improved data generation. CoraFluor™ 1 exhibits excitation upon exposure to a 337 nm UV laser, whereas CoraFluor™ 2 displays a red-shifted excitation wavelength, enhancing excitation efficiency at 365 nm and 405 nm. This attribute of CoraFluor™ 2 widens the range of analytical instruments suitable for these assays (FIGURE 1).

CoraFluor emission spectral overlap with common acceptor dyes
Figure 1: Schematic illustrating overlap of CoraFluor emission spectra with common acceptor dyes.


CoraFluor reagents can be conjugated directly to your antibody or protein of interest. We also offer custom conjugation of CoraFluor to an antibody of your choice.

TR-FRET and Targeted Protein Degradation

CoraFluor TR-FRET ternary complex assay
Figure 2: Illustration of a TR-FRET ternary complex formation assay.


TR-FRET assays are useful in the study of ternary complex formation in the development of small molecule Protein Degraders, such as PROTAC® molecules. They provide a quantitative measure of the interactions between the Degrader, the target protein, and the ubiquitin E3 ligase (FIGURE 2). Characterizing the binding affinity of the Degrader to the target protein, the recruitment of ubiquitin E3 ligase to the target protein, and the formation of a co-operative ternary complex necessary for ubiquitination and subsequent degradation, using TR-FRET assays are critical for effective targeted protein degradation research, as this allows for optimization of Degrader molecules to improve their potency and selectivity.

CoraFluor TR-FRET protein degradation quantification assay
Figure 3: CoraFluor TR-FRET protein degradation quantification assay.


TR-FRET assays provide precise quantification of target protein levels in cellular lysates following application of a Degrader, which is essential for targeted protein degradation research. In addition, TR-FRET assays are appliable to a high-throughput format on a fluorescence microplate reader. This technique offers invaluable insights into the time- and dose-dependent kinetics of degradation for a panel of candidate Degraders. Furthermore, it enables calculation of important parameters, including the DC50 (the concentration at which target protein degradation is half-maximal) and Dmax (the maximal achievable degradation level) (FIGURE 3).

Background Information

Resources

Target Protein Degradation

Targeted Protein Degradation Research Product Guide

Our Targeted Protein Degradation Research Product Guide highlights the tools and services available from Bio-Techne to support your Targeted Protein Degradation research including, Active Degraders, Degrader Building Blocks, Custom Degrader Services, Proteins and Assays for protein degradation.

BODIPY® is a registered trademark of Molecular Probes.

CoraFluor™ is a trademark of Bio-Techne Corp.

PROTAC® is a registered trademark of Arvinas Operations, Inc., and is used under license.