TR-FRET Binding Assay Service

Q: Q: What is the key difference between TR-FRET and standard FRET?

A: The key difference is the use of long-lived lanthanide donors in TR-FRET. The time-gated detection allows for the decay of short-lived background fluorescence, resulting in a much higher signal-to-noise ratio compared to standard FRET, which uses conventional fluorophores.

Q: Q: Can TR-FRET be used for low-affinity interactions?

A: Yes, TR-FRET is excellent for detecting interactions with affinities in the nM to low μM range. Its high sensitivity makes it suitable for characterizing weaker binders that might be missed by other methods.

Q: Q: What are the typical labeling strategies for a TR-FRET assay?

A: Common strategies include using labeled antibodies specific to the proteins of interest (e.g., one labeled with a donor, the other with an acceptor) or using tagged proteins (e.g., HaloTag, SNAP-tag) that can be covalently linked to TR-FRET compatible dyes.

Inquiry

CD BioSciences provides expert time-resolved FRET (TR-FRET) binding assay services. Our TR-FRET platform is designed to deliver robust, quantitative data in complex biological environments, making it an indispensable tool for epigenetic research, drug discovery, and intracellular target validation.

Overview of TR-FRET

Time-resolved FRET is a highly sensitive and versatile technology that combines the specificity of FRET (Förster Resonance Energy Transfer) with the temporal resolution of time-resolved fluorescence detection. In a TR-FRET assay, a donor molecule (typically a Lanthanide complex, such as Europium or Terbium cryptate) is excited by a light pulse. If an acceptor molecule (e.g., a fluorescent dye like d2 or XL665) is in close proximity due to a specific binding event, the energy is transferred from the donor to the acceptor, which then emits light at a specific wavelength. The key advantage is the "time-resolved" measurement, which introduces a delay between excitation and emission detection. This delay allows for the elimination of short-lived background fluorescence, significantly enhancing the signal-to-noise ratio and assay robustness.

A high-throughput TR-FRET assay.

Fig.1 A high-throughput time-resolved fluorescence resonance energy transfer (TR-FRET) detection method. (Aromokeye R, et al., 2025)

Our Services

Every project begins with a comprehensive consultation to align the assay design with your specific goals. Whether you need to rank compound potency, assess binding kinetics in a cellular context, or study co-factor dependencies in an epigenetic complex, CD BioSciences tailors the experimental strategy to deliver the most relevant and impactful data for your decision-making.

We offer comprehensive TR-FRET analysis tailored to your research objectives:

High-Throughput Screening (HTS): Support for 384-well and 1536-well formats for efficient screening of thousands of compounds.
Competitive Binding Assays: Determine the half-maximal inhibitory concentration (IC50) of unlabeled competitors.
Direct Binding Assays: Quantify binding affinity (EC50) between labeled partners.
Cellular Target Engagement: Validate compound binding to intracellular targets in a cell-based format.

Service Workflow

Sample Requirements

Protein/Protein Complex: High purity (>90%), known concentration, buffer information.
Small Molecule Compound: High purity (>95%), preferably soluble in DMSO or aqueous buffer.
Cell Lysates (for cellular assays): Specific cell type, number of cells, and preparation method details.

Deliverables

Upon project completion, you will receive:

A detailed final report including all experimental parameters and conditions.
All original data files (e.g., plate reads, dose-response curves).
Calculated parameters (e.g., Z'-factor, IC50, EC50, Hill Slope).
Professional interpretation and conclusions.

Why Choose Us?

Advanced Cellular Profiling: We go beyond simple in vitro binding. Our service includes live-cell TR-FRET assays to validate target engagement within the native cellular environment, providing critical data on membrane permeability and intracellular efficacy for drug candidates. This is essential for confirming that your epigenetic modulator actually reaches its intended target inside the cell.
Specialized Epigenetic Assay Development: We have pre-validated, off-the-shelf assays for high-demand targets like BET bromodomains, HDACs, and various methyltransferases. For novel targets, our experts develop custom assays using labeled antibodies or tagged proteins (e.g., HaloTag, SNAP-tag) to ensure high specificity and a robust signal window for your unique research needs.

Frequently Asked Questions (FAQs)

Q: What is the key difference between TR-FRET and standard FRET?

Q: Can TR-FRET be used for low-affinity interactions?

Q: What are the typical labeling strategies for a TR-FRET assay?

CD BioSciences doesn't just run the experiment, we provide deep analytical support. We help you interpret complex data, such as distinguishing between allosteric and competitive inhibition mechanisms based on the TR-FRET signal pattern. We also assist in troubleshooting common issues like compound interference or high background, ensuring you receive clear, actionable results. Contact us today for a detailed consultation to discuss your specific project requirements, request a comprehensive quote.

Reference

1. Aromokeye R, Ackerman-Berrier M, et al. Development of a high-throughput TR-FRET assay to identify inhibitors of the FAK-paxillin protein-protein interaction[J]. SLAS Discovery, 2025, 34: 100237.