Thermal Shift Assay for Ligand Binding in Non-Purified Samples
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Solution Overview
Problem
Current methods for detecting protein-ligand binding interactions are limited as they require purified proteins and cannot effectively analyze non-purified samples, such as those found in cells or tissues, which are crucial for understanding drug interactions and therapeutic efficiency.
Innovation Solution
A thermal shift assay method that separates soluble from insoluble proteins after heat treatment to detect ligand binding in non-purified samples without relying on enzymatic activity of tags or fusion proteins, allowing for the analysis of thermal stability changes indicative of ligand binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If purified proteins are used for detection, then measurement precision is improved, but device complexity and sample preparation requirements increase
Solution Approach 1:
The invention extracts the essential detection function from complex purified protein samples by using thermal shift assays that detect ligand binding through temperature-induced solubility changes. This allows detection in non-purified samples by separating the detection principle from the requirement for protein purification, thereby maintaining measurement precision while reducing sample preparation complexity
Solution Approach 2:
The invention changes the detection parameter from requiring purified protein states to detecting thermal stability changes (melting temperature shifts) that occur upon ligand binding. This parameter change enables the use of non-purified samples while maintaining detection accuracy, as the thermal shift signal remains detectable regardless of sample purity
2Ease of operation
If non-purified samples are analyzed, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The invention exploits the phase transition of proteins from soluble to insoluble states upon heating (thermal denaturation). By monitoring the melting temperature shift of target proteins in non-purified samples, the method maintains measurement precision while enabling easy operation with complex biological samples, as the phase transition provides a clear detectable signal regardless of sample purity
Solution Approach 2:
The invention introduces thermal energy as an intermediary that induces measurable changes in protein solubility. This intermediary allows the detection system to distinguish ligand-bound from unbound protein states in non-purified samples through temperature-dependent solubility changes, maintaining precision while simplifying sample handling
3Measurement precision
If enzymatic activity of tags or fusion proteins is used for detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention replaces enzymatic detection systems with a thermal physics-based detection method. Instead of using enzymatic activity of tags or fusion proteins, the method detects ligand binding through temperature-induced solubility changes and melting temperature shifts, thereby reducing detection system complexity while maintaining measurement precision through physical property measurements
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
Enables the detection of ligand binding in non-purified samples, providing a generic and efficient method for investigating protein-ligand interactions in complex biological samples, which is essential for drug development and understanding therapeutic efficiency.
Implementation Method 1
heating the non-purified target protein and ligand
Implementation Method 2
separating soluble from insoluble proteins after heat treatment to estimate the amount of soluble target protein and thus thermally stable ligand bound target protein
Data Source
AI summary
The invention is directed to a method of determining whether a non-purified sample contains a target protein bound to a ligand of interest comprising the steps of: a) exposing said non-purified sample to a temperature which is capable of causing or enhancing precipitation of the unbound target protein to a greater extent than it is capable of causing or enhancing precipitation of the target protein bound to said ligand; b) processing the product of step a) in order to separate soluble from insoluble protein; and c) analyzing either or both the soluble and insoluble protein fractions of step b) for the presence of target protein, wherein said target protein is not detected on the basis of enzymatic activity of a tag, peptide, polypeptide or protein fused thereto. Particularly, the invention may be used to determine whether drugs can bind to their protein targets in samples derived from patients to ascertain whether a certain drug can be used in a therapy for that patient. Additionally, the invention is directed to an instrument for use in the methods of the invention and use of a kit in the methods of the invention comprising an antibody and/or a non-protein fusion tag.