AAV Binding Polypeptides for Full Capsid Purification
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Solution Overview
Problem
Current methods for purifying adeno-associated virus (AAV) capsids are inefficient, as they struggle to selectively separate full capsids from empty and partial capsids due to similarities in their external surfaces, affecting the efficacy and safety of gene therapy compositions.
Innovation Solution
Development of polypeptides that preferentially bind to full AAV capsids, allowing for their selective separation from empty capsids using compositions comprising specific amino acid sequences that exhibit a two-fold increase in binding preference for full capsids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If charge-based separation methods (ion exchange chromatography) are used, then separation of full from empty capsids is achieved, but the method is inefficient and complex
Solution Approach 1:
The patent introduces a polypeptide binder as an intermediary substance that selectively interacts with full capsids through specific binding to the VP2 protein. This mediator enables separation without requiring complex charge-based chromatography systems, simplifying the overall separation process while maintaining high purity.
Solution Approach 2:
The invention replaces complex mechanical separation systems (ultracentrifugation, ion exchange chromatography) with a simpler biochemical binding approach. The polypeptide binder uses molecular recognition and affinity binding to achieve separation, substituting complex mechanical/physical systems with a more elegant biochemical mechanism.
2Manufacturing precision
If density-based separation methods (gradient density ultracentrifugation) are used, then capsid separation is achieved, but the method is inefficient and time-consuming
Solution Approach 1:
The polypeptide binder serves as a selective intermediary that rapidly captures full capsids through specific affinity binding to VP2 proteins. This biochemical mediator enables fast, efficient separation without requiring prolonged ultracentrifugation processes, dramatically improving productivity while maintaining separation purity.
Solution Approach 2:
The invention changes the separation parameter from physical density (requiring ultracentrifugation) to biochemical affinity (requiring only binding conditions). By altering the separation mechanism from density-based to affinity-based, the process becomes much faster and more efficient, resolving the productivity issue.
3Ease of operation
If external capsid surface similarities are exploited for purification, then separation is simplified, but full and empty capsids cannot be distinguished
Solution Approach 1:
The patent applies local quality by focusing the binding interaction on a specific local region of the capsid surface - the VP2 protein domain that differs between full and empty capsids. Rather than treating the entire capsid surface uniformly, the polypeptide binder targets a specific local epitope, enabling differentiation despite overall surface similarities.
Solution Approach 2:
Instead of trying to find differences in the external capsid surface to separate full from empty capsids (the conventional approach), the invention inverts the strategy by using a binder that specifically recognizes and binds to full capsids through VP2 interaction. This inversion allows selective capture of full capsids while leaving empty capsids unbound, achieving separation through positive selection rather than negative differentiation.
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
The polypeptides effectively separate full AAV capsids from empty capsids, enhancing the purity and safety of gene therapy compositions by improving the selective quantification and purification of full capsids.
Implementation Method 1
compositions comprising polypeptides that bind preferentially to full AAV capsids
Data Source
AI summary
Disclosed herein are AAV binding proteins and methods of making and using the same.