ISVD Binding Agents Stabilize CFTR NBD1 Domain
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Solution Overview
Problem
Current treatments for cystic fibrosis, particularly those targeting the F508del mutant of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, fail to effectively stabilize the protein, leading to limited therapeutic efficacy due to the proteins' intrinsic dynamics and instability.
Innovation Solution
Development of immunoglobulin single variable domains (ISVDs) that bind specific sites on the nucleotide-binding domain 1 (NBD1) of CFTR, increasing its thermal stability by at least 5°C, thereby rescuing the protein from proteasomal degradation and facilitating its maturation and function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current treatments target the F508del mutant CFTR, then therapeutic efficacy is improved, but the protein stability is insufficient leading to continued degradation
Solution Approach 1:
The patent introduces ISVDs as intermediary molecules that bind to the NBD1 domain of F508del CFTR, acting as stabilizing agents that prevent proteasomal degradation. These ISVDs serve as a mediator between the mutant protein and the cellular quality control system, providing therapeutic efficacy while improving protein stability through specific binding interactions.
Solution Approach 2:
The patent applies parameter changes by modifying the thermal stability parameter of CFTR through ISVD binding. The ISVDs increase the melting temperature of the mutant protein, changing its thermodynamic parameters to prevent degradation and promote proper folding and trafficking to the cell surface.
2Productivity
If the CFTR protein is stabilized, then functional expression is improved, but the intrinsic dynamics and instability remain challenging
Solution Approach 1:
The patent addresses the dynamic nature of CFTR by using ISVDs that bind to specific conformational states of the NBD1 domain. The ISVDs stabilize particular dynamic conformations of the mutant protein, preventing degradation while maintaining the protein's functional dynamics and enabling proper trafficking and activity.
3Temperature
If ISVDs bind to NBD1 of CFTR, then thermal stability increases by at least 5°C, but the binding specificity must be precise
Solution Approach 1:
The patent applies local quality by designing ISVDs with specific complementarity determining regions (CDRs) that target precise local epitopes on the NBD1 domain. This localized binding approach ensures high specificity and thermal stability enhancement at the binding site while maintaining overall protein function.
Solution Approach 2:
The patent uses computational methods and structural biology to replace trial-and-error approaches with rational design. Crystal structures and computer-assisted methods are employed to identify and validate binding interfaces, ensuring precise ISVD-CFTR interactions that achieve the desired thermal stability with high binding specificity.
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 ISVDs significantly enhance the thermal stability and functional expression of both wild-type and F508del mutant CFTR proteins, offering a promising therapeutic approach by increasing the melting temperature and promoting proper folding and trafficking to the cell surface.
Implementation Method 1
the immunoglobulin single variable domains (ISVDs) identified herein reveal novel binding sites on the nucleotide-binding domain 1 of CFTR
Implementation Method 2
which allow to rescue pathogenic mutant F508del CFTR from proteasomal degradation. The binding agents are therefore considered suitable in treatment of cystic fibrosis. Finally, also crystal structures demonstrating binding interfaces, and computer-assisted methods for selecting molecules able to stabilize CFTR are described.
Implementation Method 3
which allow to rescue pathogenic mutant F508del CFTR from proteasomal degradation
Implementation Method 4
promoting proper folding and trafficking to the cell surface
Data Source
AI summary
The present invention relates to binding agents specific for the cystic fibrosis transmembrane conductance regulator (CFTR), which increase its thermal stability to provide for potent therapeutics. More particular, the immunoglobulin single variable domains (ISVDs) identified herein reveal novel binding sites on the nucleotide-binding domain 1 of CFTR, which allow to rescue pathogenic mutant F508del CFTR from proteasomal degradation. The binding agents are therefore considered suitable in treatment of cystic fibrosis. Finally, also crystalline structures demonstrating binding interfaces, and computer-assisted methods for selecting molecules able to stabilize CFTR are described.