DNA-Encoded Bead Screening Assay for Cellular Target Identification
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Solution Overview
Problem
Current screening assays for small molecules in cellular contexts face challenges such as high logistics complexity and time requirements for analyzing large numbers of compounds, with prior art methods often resulting in a high false discovery rate of non-hit beads and inefficient bead population management.
Innovation Solution
A method involving DNA-encoded beads where chemical structures and their encoding DNA are covalently linked, with cleavable linkers that allow for controlled release and sequencing, enabling the pooling and identification of hit beads independently of the initial bead population, reducing the number of microcompartments needed and improving hit bead isolation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If small molecules are screened in cellular assays using microplates with many wells, then the diversity of compounds that can be screened increases, but the time required to assess product formation increases linearly and logistics complexity increases
Solution Approach 1:
The invention divides the screening process into two independent phases: (1) a binding assay phase where small molecules are screened for target binding using microplates with many wells, and (2) a cellular assay phase where only the hit molecules from phase 1 are tested in cellular contexts. This segmentation allows the binding assay to handle large compound diversity in parallel while reducing the time-consuming cellular assessment to only a small subset of compounds.
Solution Approach 2:
The binding assay is performed as a preliminary screening step before the cellular assay. By pre-identifying hit molecules that bind to the target in the binding assay, the invention eliminates the need to perform time-consuming cellular assays on all compounds in the library, thus reducing overall screening time while maintaining the ability to screen diverse compound libraries.
2Ease of manufacture
If DNA-encoded chemical libraries are used to identify compound structures, then structure determination becomes standardized through DNA sequencing, but the compounds linked to DNA tags may not behave identically in the assay as free compounds
Solution Approach 1:
The invention extracts the small molecule from the DNA-encoded bead complex during the binding assay. The small molecule is released from the bead and allowed to interact with the target protein in solution, ensuring that the actual binding event involves the free compound rather than the bead-bound compound. This extraction step resolves the reliability issue by ensuring that hit identification reflects the behavior of free compounds.
Solution Approach 2:
The invention uses the bead as an intermediary carrier during the binding assay setup, but the small molecule is released to act as the actual intermediary between the compound library and the target protein. The bead facilitates the organized presentation of compounds during setup but does not interfere with the actual binding interaction, thus maintaining both standardization benefits and behavioral equivalence.
3Productivity
If all beads are pooled and hits are isolated after screening, then the number of microcompartments needed is reduced and false discovery rate is minimized, but the complexity of bead manipulation and isolation increases
Solution Approach 1:
The invention employs fluorescently labeled beads that change their optical properties based on assay outcome. Hit beads are identified and isolated based on fluorescence signal characteristics, allowing for automated optical sorting rather than manual manipulation. This color/fluorescence-based identification system reduces the complexity of bead handling while enabling high-throughput processing of pooled bead samples.
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 significantly reduces the number of microcompartments required for screening and minimizes false discovery rates, allowing for more efficient identification of active chemical structures by pooling all beads and isolating hits, thereby enhancing the throughput and accuracy of the screening process.
Implementation Method 1
releasing the chemical structures from the bead(s) in the incubation medium by cleaving the structure linkers at the cleavable structure linker site
Implementation Method 2
the fluorophore and the quencher, wherein the quencher upon removal of the quencher from the fluorophore, light is emitted by the fluorophore
Data Source
AI summary
A method for screening a DNA-encoded library of chemical structures (2) for activity in a cellular target (11) wherein the chemical structures (2) of the library, the corresponding encoding DNA (4) and, optionally, a chemical probe (7/8/9) susceptible to the response molecule (12) are covalently linked to beads (1); the method comprising providing an incubation medium (13) or aliquot thereof comprising the cellular target (11) and exactly one or more than one bead (1) as defined above, releasing the chemical structures (2) from the bead(s) (1) in the incubation medium (13) or aliquots thereof by cleaving the structure linkers (3) and incubating the released chemical structures (2) and the cellular target (11); and sequencing the encoding DNA present or remaining on the bead(s) (1). A bead (1) suited for the method is also provided.