BRET Assay for Intracellular Target Binding Detection

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Solution Overview

Problem

Current methods for identifying the targets of bioactive agents within living cells are inefficient due to insufficient capture, high background noise, and inability to detect weak interactions, leading to high failure rates in determining target engagement and specificity.

Innovation Solution

The use of BRET assay systems comprising a bioactive agent tethered to a fluorophore and a cellular target fused to a bioluminescent reporter, allowing for the detection of interactions through energy transfer between the fluorophore and bioluminescent reporter upon binding, enabling accurate characterization of binding affinity and specificity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If bi-functionalized compounds are used for target enrichment, then target capture is improved, but background noise increases due to non-specific binding

Engineering Contradiction:
Improvetarget capture efficiencyVSAvoidnon-specific binding background
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The invention uses a bioluminescent reporter as an intermediary between the cellular target and the detection system. The reporter emits light that can be detected without direct contact between the detection reagent and the target, reducing non-specific binding. The light emission serves as a mediator that translates molecular binding events into detectable signals while minimizing background interference from non-specific interactions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces mechanical/chemical binding-based detection (which suffers from non-specific binding) with an optical detection system based on bioluminescence resonance energy transfer (BRET). Instead of relying on physical separation or washing steps to remove non-specifically bound compounds, the system uses energy transfer between the bioluminescent reporter and a fluorophore to generate a specific detectable signal that is insensitive to non-specific binding background.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If covalent binding is used to enhance target capture, then binding affinity is improved, but target isolation efficacy decreases due to loss of reversibility

Engineering Contradiction:
Improvebinding affinityVSAvoidtarget isolation efficacy
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention replaces covalent binding (irreversible chemical modification) with a BRET-based detection system that measures binding through energy transfer. This allows for reversible, non-covalent interactions to be detected with high sensitivity, maintaining both the reversibility needed for reliable target isolation and the affinity required for specific detection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of information

If traditional enrichment methods are used, then target identification is achieved, but false positive interactions increase due to solid support binding

Engineering Contradiction:
Improvetarget identification accuracyVSAvoidfalse positive interactions
Core Design Contradiction:
Loss of informationVSObject-generated harmful factors

Solution Approach 1:

The bioluminescent reporter acts as an intermediary that eliminates the need for solid support binding in the detection step. The light signal is generated in solution phase through energy transfer, avoiding the introduction of solid supports that cause non-specific binding and false positives. The detection occurs through optical energy transfer rather than physical adsorption.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces solid support-based detection with solution-phase BRET detection. By using bioluminescence resonance energy transfer between the reporter and fluorophore in solution, the system eliminates the need for solid supports that introduce non-specific binding sites, thereby reducing false positive interactions while maintaining target identification accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If high concentration of compounds is used for screening, then phenotypic response detection is improved, but off-target interactions increase

Engineering Contradiction:
Improvescreening efficiencyVSAvoidoff-target interactions
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention replaces traditional high-concentration screening with BRET-based detection that achieves high sensitivity at low compound concentrations. The energy transfer mechanism provides a large signal amplification effect, allowing detection of binding events at physiologically relevant low concentrations, thereby maintaining screening efficiency while minimizing off-target interactions that occur at high concentrations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides a robust and unbiased method for detecting and analyzing the binding of bioactive agents to cellular targets, reducing false positives and improving the identification of specific interactions, even for compounds with low affinity or off-target effects.

Implementation Method 1

The use of BRET assay systems comprising a bioactive agent tethered to a fluorophore and a cellular target fused to a bioluminescent reporter, allowing for the detection of interactions through energy transfer between the fluorophore and bioluminescent reporter upon binding

Methodology Applied
Scientific EffectBioluminescence resonance energy transfer (BRET): Bioluminescence

Implementation Method 2

a bioactive agent tethered to a chromophore (e.g., fluorophore)... the emission spectrum of the bioluminescent reporter overlaps with the absorption spectrum of a fluorophore

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3712154A1Recognition of cellular target binding by a bioactive agent using intracellular bioluminescence resonance energy transfer
Publication Date: 2020.09.23 PROMEGA CORP
  • EP3712154A1 patent drawingFigure 1A~1D
  • EP3712154A1 patent drawingFigure 2
  • EP3712154A1 patent drawingFigure 2

AI summary

The present invention provides compositions and methods for detection and analysis of intracellular binding of a bioactive agent to a cellular target. In particular, provided herein are bioactive agents tethered to fluorophores, cellular targets fused to bioluminescent reporters, or portions, components, or subunits of bioluminescent reporters, and methods of detecting and analyzing the interaction of bioactive agents with cellular targets therewith.