Fluorescence Polarization Binding Assay

Q: Q: What is the main advantage of fluorescence polarization over other binding assays?

A: Fluorescence polarization is a true homogeneous assay, meaning no separation steps are needed. It is exceptionally well-suited for high-throughput screening due to its simplicity, speed, and cost-effectiveness, especially for studying small molecule-protein interactions.

Q: Q: What types of interactions are best studied with fluorescence polarization?

A: Fluorescence polarization is ideal for studying interactions where a small, fluorescently-labeled molecule (like a drug candidate or peptide) binds to a much larger molecule, such as a protein. The significant change in molecular size upon binding produces a strong polarization signal.

Q: Q: Can fluorescence polarization be used for very high-affinity interactions?

A: Fluorescence polarization is excellent for characterizing interactions with affinities in the nM to μM range. For extremely high-affinity (pM) interactions, the very low tracer concentrations required can sometimes be challenging, but competitive assays are often a viable alternative.

Inquiry

CD BioSciences delivers high-performance fluorescence polarization binding assay services designed for rapid, quantitative analysis of molecular interactions in a homogeneous solution format. Our fluorescence polarization platform excels in small molecule screening and competitive binding studies, providing a cost-effective and robust solution for epigenetic target validation and drug discovery programs.

Overview of Fluorescence Polarization

Fluorescence polarization is a versatile, solution-based technique that measures the change in polarization of fluorescent light emitted from a labeled molecule upon binding to a larger partner. When a small, fluorescently-labeled molecule is excited with polarized light, it rotates rapidly in solution, resulting in low polarization. However, when it binds to a larger molecule (e.g., a protein), its rotation slows significantly, leading to a measurable increase in fluorescence polarization. This change directly correlates with the fraction of bound ligand, allowing for quantitative analysis of binding affinity and kinetics.

Application of fluorescence polarization (FP) in the detection of ADPr-binding macrodomains.

Fig.1 Design and mechanism of a fluorescence polarization (FP) assay for ADPr-binding macrodomains. (Anmangandla A, et al., 2023)

Our Services

Leveraging state-of-the-art microplate readers and optimized assay protocols, CD BioSciences' fluorescence polarization service is designed for efficiency and scalability. We specialize in developing robust fluorescence polarization assays that provide reliable data to accelerate your early-stage discovery and screening efforts.

We offer comprehensive fluorescence polarization 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

Samples and Applications

Supported Sample Types

Potein-based samples: Purified proteins, protein lysates, recombinant proteins, antibodies.
Nucleic acids: DNA, RNA, oligonucleotides.
Small molecules: Drug compounds, metabolites, inhibitors.
Cellular samples: Cell lysates, membrane preparations, tissue extracts.
Biological fluids: Serum, plasma, urine, cerebrospinal fluid.

Diverse Application Scenarios

Protein-protein interactions: binding affinity measurements between protein partners.
Protein-ligand interactions: small molecule binding to target proteins.
Protein-DNA/RNA interactions: transcription factor binding studies.
Antigen-antibody binding: immunological assays and epitope mapping.
Enzyme-substrate/inhibitor interactions: kinetic and inhibition studies.
Receptor-ligand binding: membrane receptor studies using solubilized receptors.

Why Choose Us?

Expertise in Challenging Target Assay Development: Beyond standard assays, we excel at developing custom fluorescence polarization solutions for difficult targets, including novel epigenetic readers and enzymes for your specific molecular system.
Integrated Analysis from Screening to Characterization: We don't just deliver raw polarization values; we provide full dose-response curves, precise IC50 values for inhibitors, and expert interpretation of binding mechanisms.
Focus on Epigenetic Targets: Leveraging our broad experience in epigenetics, we understand the unique challenges and requirements of studying targets like bromodomains, histone-modifying enzymes, and transcription factors.

Frequently Asked Questions (FAQs)

Q: What is the main advantage of fluorescence polarization over other binding assays?

Q: What types of interactions are best studied with fluorescence polarization?

Q: Can fluorescence polarization be used for very high-affinity interactions?

When you partner with us, you gain more than just data—you gain a strategic advantage in early-stage discovery and screening. CD BioSciences' focused expertise and optimized platforms ensure you receive the most reliable, high-quality information to accelerate your project timeline and inform critical decisions. Contact us today for a detailed consultation to discuss your specific project requirements, request a comprehensive quote.

Reference

1. Anmangandla A, Jana S, Peng K, et al. A fluorescence polarization assay for macrodomains facilitates the identification of potent inhibitors of the SARS-CoV-2 macrodomain[J]. ACS chemical biology, 2023, 18(5): 1200-1207.