Multipartite Fusion Molecule Protein Stability Screening
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Solution Overview
Problem
Current methods for expressing stable and functional proteins in heterologous systems, such as E. coli, face challenges in achieving high yields and stability, leading to high production costs and inefficiencies, particularly for pharmaceutical proteins like G-CSF, due to protein aggregation and stability issues.
Innovation Solution
The use of multipartite fusion molecules with screenable markers like β-lactamase, where the gene of interest is inserted into a host cell with a screenable marker, allowing for selection and screening of stable variants under antibiotic stress, enabling the identification of proteins with enhanced stability and expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional expression methods are used in E. coli, then production cost is reduced and expression speed is improved, but protein stability deteriorates and aggregation increases
Solution Approach 1:
The patent uses a fusion partner protein as an intermediary between the target protein and the E. coli expression system. This fusion partner mediates the interaction by providing solubility enhancement and proper folding assistance, allowing the target protein to express stably in the heterologous E. coli system without direct contact between the unstable target protein and the potentially harmful bacterial environment.
Solution Approach 2:
The patent creates a composite protein structure by fusing the target protein with a stabilizing partner protein. This composite fusion protein combines the functional domain of the target protein with the solubility and stability properties of the partner protein, resulting in a hybrid molecule that expresses better in E. coli while maintaining the functional characteristics of the original target protein.
2Productivity
If high-level expression is achieved, then productivity is improved, but protein aggregation increases and solubility decreases
Solution Approach 1:
The patent changes the physical-chemical parameters of the expression system by introducing fusion partners with different solubility characteristics, molecular weights, and structural properties. This parameter modification allows the system to achieve high expression levels while maintaining solubility, as the fusion partner alters the aggregation propensity and solubility parameters of the target protein.
Solution Approach 2:
The fusion partner acts as a mediator that prevents direct aggregation between target protein molecules at high concentrations. By inserting the target protein into a soluble fusion context, the intermediary partner maintains molecular spacing and prevents unwanted interactions that lead to aggregation, enabling high-level expression without loss of solubility.
3Measurement precision
If screening methods are improved to identify stable variants, then measurement precision is improved, but device complexity and screening time increase
Solution Approach 1:
The patent merges the stability selection function with the antibiotic resistance selection function by fusing the target protein into the beta-lactamase gene. This combination allows a single screening step to simultaneously select for both antibiotic resistance and protein stability, eliminating the need for separate stability assessment procedures and reducing overall screening system complexity.
Solution Approach 2:
The beta-lactamase fusion construct serves multiple functions: it provides antibiotic resistance for selection, enables stability-based screening through differential resistance, and maintains solubility enhancement. This multi-functional design consolidates multiple screening requirements into a single universal system, reducing the number of separate devices and procedures needed.
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 allows for the efficient selection and stabilization of proteins, increasing their stability and expression levels, reducing production costs and improving the yield of therapeutic proteins by correlating antibiotic resistance with protein stability, thereby enhancing the production of stable and functional proteins.
Implementation Method 1
introducing one or more expression constructs encoding a multipartite fusion molecule... wherein the expression constructs comprises a first gene encoding a molecule of interest inserted into or associated with a second gene that encodes a screenable (e.g., selectable) phenotype... culturing the host cells under conditions such that fusion molecules comprising an functional selectable or screenable marker gene are selected or screened for
Data Source
AI summary
The present invention relates to methods and compositions for enhancing folding and stability of biological molecules. In particular, the present invention relates to methods and compositions for identifying biological molecules with enhanced stability. The present invention further relates to host cells that confer enhanced stability to biological molecules expressed therein.