Ligand Affinity Ranking via Competitive Filtration

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Solution Overview

Problem

Current methods for determining the affinity of ligands with targets, such as enzymes, are either complex, imprecise, or limited in scalability, often requiring multiple analyses or distorting the target's activity, making it difficult to classify ligands by their affinity effectively.

Innovation Solution

A method involving a mixture of ligands with a target, where a reference ligand with known affinity is added, allowing for precise relative quantification of ligands by filtration and chromatographic analysis, enabling the identification of ligands with the highest affinity without modifying the target, and allowing for a large number of ligands to be processed in a single experiment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If phage display technique is used to isolate ligands, then all ligands with affinity can be identified, but they cannot be ranked according to affinity to select the most effective ones

Engineering Contradiction:
Improveligand identification completenessVSAvoidaffinity ranking precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary substance (competitive ligand with known affinity) that mediates the interaction between the target and the ligand mixture. This intermediary competes for binding sites, allowing the relative affinities of different ligands to be quantified through displacement experiments, thereby enabling precise affinity ranking while maintaining complete ligand identification

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the concentration parameter of the competitive ligand systematically to observe displacement effects. By varying the concentration of the reference ligand and measuring the corresponding changes in bound ligand amounts, the method transforms qualitative binding information into quantitative affinity measurements, enabling precise ranking

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If centrifugation is used to separate ligand-macromolecule complexes, then classification by affinity is possible, but the process is complex and separation is difficult

Engineering Contradiction:
Improveaffinity classification precisionVSAvoidseparation process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the separation step from the complex centrifugation process and replaces it with a simpler filtration approach. By using filtration to separate free ligands from bound ligands, the method eliminates the complexity of centrifugation while maintaining affinity classification precision through the competitive binding assay

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If ligands are passed through a column with attached target molecules, then ligands can be classified by affinity, but the target's activity is denatured

Engineering Contradiction:
Improveaffinity classification precisionVSAvoidtarget activity preservation
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent uses a soluble target protein as an intermediary in solution-phase binding reactions, avoiding the need to immobilize the target on a column. This intermediary approach allows affinity classification through competitive binding assays while preserving target activity, as the target remains in its native conformational state without surface attachment constraints

Inventive Principle:
Principle #24Intermediary (Mediator)

4Quantity of substance

If MALDI-TOF analysis is used to identify ligands, then binding information can be obtained, but background noise from the matrix makes identification difficult

Engineering Contradiction:
Improveligand detection capabilityVSAvoidligand identification precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent extracts and removes the problematic matrix component from the analysis system. By using mass spectrometry without the MALDI matrix or employing alternative detection methods that do not require matrix addition, the method eliminates background noise while maintaining the ability to detect and quantify ligands with high precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent substitutes the MALDI-TOF mechanical ionization system with an alternative analytical approach. By using electrospray ionization or other soft ionization techniques coupled with mass spectrometry, the method achieves ligand identification without the background noise problems inherent in matrix-assisted laser desorption

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 method provides a simple, reliable, and precise way to determine ligand affinity, eliminating variability and allowing for the selection of the most effective ligands without target modification, enabling the classification of numerous ligands in one day and applying to targets with no enzymatic activity.

Implementation Method 1

a mixture is prepared with a target and a sample consisting of a mixture of ligands so that the ligands with an affinity for the target bind to it

Methodology Applied
Scientific EffectAffinity binding: Absorption (physical)

Implementation Method 2

The mixture is filtered to retain only the target-ligand complexes

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP3516395B1Method for determining affinity between ligands and a target
Publication Date: 2020.10.14 PLANT ADVANCED TECHNOLOGIES PAT SAS
  • EP3516395B1 patent drawingFigure 1~2
  • EP3516395B1 patent drawingFigure 3A~3C
  • EP3516395B1 patent drawing

AI summary

The invention relates to a method for determining the affinity between ligands and a target. According to said method, a mixture is prepared with a target and a sample formed from a mixture of ligands in controlled proportions so that the ligands having an affinity with the target bind thereto; the mixture is filtered so as to keep only the target-ligand complexes; the separation of the target-ligand complexes is provoked; the ligands and the targets are separated; the ligands are recovered by filtration in a treated solution and said treated solution is analysed to identify the presence of the ligands; the treated solution being analysed by relatively quantifying the ligands, the ligands present in a larger quantity having the greatest affinity with the target.