Transmembrane Protein Screening Using Plant ER Microsomes
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Solution Overview
Problem
Current high-throughput screening (HTS) methods for transmembrane proteins (TPs) are limited by the difficulty in producing correctly folded and stabilized TPs, which are crucial drug targets, due to challenges in expression, post-translational modification, and the complexity of cell membranes, leading to low throughput and high costs.
Innovation Solution
A plant-based cell-free protein synthesis system using endogenous microsomes from tobacco BY-2 cells provides a platform for synthesizing TPs embedded in lipid bilayers, allowing for high-throughput screening of ligands by maintaining native protein biosynthesis machinery and avoiding artificial components, with methods for capturing and detecting TPs on biologically non-active surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional HTS methods are used for transmembrane proteins, then screening can be performed, but the throughput is limited and costs are high due to difficulties in producing correctly folded TPs
Solution Approach 1:
The patent extracts transmembrane proteins from their native cellular environment and incorporates them into artificial lipid bilayers formed around water-in-oil emulsion droplets. This extraction allows TPs to be produced in a simplified cell-free system using plant-based extracts, eliminating the need for complex living cell cultures while maintaining protein folding and function. The TPs are expressed in vitro and self-assemble into functional membrane structures within the emulsion droplets, enabling high-throughput screening.
Solution Approach 2:
The patent uses lipid bilayers formed around water-in-oil emulsion droplets as an intermediary environment for transmembrane proteins. These artificial membranes serve as a mediator that provides the necessary hydrophobic environment for TP insertion and folding, while the water-in-oil emulsion format enables easy manipulation, stabilization, and high-throughput handling. The emulsion droplets act as discrete reaction chambers that facilitate screening while maintaining protein functionality.
2Measurement precision
If recombinant technology is used for target-based screening, then specific ligand identification is possible, but the process is time-consuming and expensive
Solution Approach 1:
The patent performs preliminary actions by pre-forming stable water-in-oil emulsion droplets containing functional transmembrane proteins before the actual screening process. The TPs are expressed and incorporated into lipid bilayers in advance, and the emulsion droplets are stabilized with appropriate surfactants. This preliminary preparation creates ready-to-use screening units that can be rapidly tested against ligand libraries, eliminating the need for time-consuming protein purification and membrane reconstitution during the screening process itself.
Solution Approach 2:
The patent changes the physical and chemical parameters of the screening system by using water-in-oil emulsions instead of traditional aqueous buffers. This parameter change allows for improved stability of transmembrane proteins, enhanced ligand penetration through the lipid bilayer, and facilitates high-throughput handling. The emulsion format enables better control of reaction conditions and improves the signal-to-noise ratio in binding assays, thereby reducing screening time while maintaining accuracy.
3Ease of manufacture
If artificial membrane components are used for TP expression, then protein production is simplified, but the native protein biosynthesis machinery is lost
Solution Approach 1:
The patent employs a self-service approach where plant-based cellular extracts contain all the necessary native protein biosynthesis machinery required for correct TP folding, post-translational modifications, and membrane insertion. The system uses endogenous enzymes, chaperones, and lipid metabolism pathways present in the plant extracts to autonomously produce functional transmembrane proteins. This self-service mechanism ensures native-like protein processing while maintaining the simplified cell-free format, eliminating the need for external supplementation of complex biological factors.
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 enables fast and reproducible identification of ligands as drug candidates, overcoming the limitations of existing HTS by providing high yields of correctly folded TPs, reducing reaction times and costs, and enabling multiplex screening for drug candidates associated with diseases.
Implementation Method 1
A plant-based cell-free protein synthesis system using endogenous microsomes from tobacco BY-2 cells provides a platform for synthesizing TPs embedded in lipid bilayers
Implementation Method 2
synthesizing TPs embedded in lipid bilayers, allowing for high-throughput screening of ligands by maintaining native protein biosynthesis machinery
Implementation Method 3
with methods for capturing and detecting TPs on biologically non-active surfaces
Implementation Method 4
contacting of the at least one TP with the at least one analyte and detection of interaction between the at least one analyte and the at least one TP
Data Source
AI summary
A high-throughput screening for at least one ligand of at least one transmembrane protein (TP) of interest that is embedded in a lipid bilayer of at least one endogenous microsome derived from plant-based endoplasmatic reticulum (ER). The screening includes providing at least one endogenous microsome that includes at least one lipid bilayer embedded TP or at least one endogenous microsomal fragment that includes at least one lipid bilayer embedded TP, and providing at least one analyte of interest, contacting of the at least one TP with the at least one analyte and detection of interaction between the at least one analyte and the at least one TP. The screening is suitable for high multiplex grades of TPs and analytes and for a fast and reproducible identification of ligands as potential drug candidates. All essential products, consumables and kits for use in the high-throughput screening are described.