Modified FYN SH3 Domain Binding Proteins for Targeted Recognition
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Solution Overview
Problem
Current binding agents, such as monoclonal antibodies, face limitations in stability, immunogenicity, and accessibility for intracellular targets, making them less suitable for therapeutic and diagnostic applications, while existing SH3 domains have limited specificity and affinity for non-natural targets.
Innovation Solution
Development of recombinant binding proteins derived from the Src homology 3 (SH3) domain of the FYN kinase with modified RT and src loops to enhance specificity and affinity for non-natural targets, maintaining high sequence identity to the native FYN SH3 domain outside the loops, and fusion proteins with these binding proteins for therapeutic and diagnostic applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If monoclonal antibodies are used as binding agents, then high affinity and specificity to targets can be achieved, but stability and immunogenicity are limited
Solution Approach 1:
The invention extracts the binding function from the complex antibody structure and transfers it to a simplified protein scaffold (SH3 domain). By taking out only the essential binding capability while removing the immunogenic antibody framework, the invention achieves high affinity and specificity without the associated immunogenicity and stability limitations of monoclonal antibodies.
Solution Approach 2:
The invention changes the fundamental parameters of the binding agent by substituting the antibody protein scaffold with an SH3 domain scaffold. This parameter change in the protein framework fundamentally alters the immunogenicity and stability characteristics while preserving the binding function through engineered specificity in the RT and n-Src loops.
2Reliability
If standard SH3 domains are used for binding, then simplicity and reduced immunogenicity are achieved, but specificity and affinity for non-natural targets are limited
Solution Approach 1:
The invention applies local quality changes by specifically modifying the RT and n-Src loops of the SH3 domain while keeping the rest of the scaffold unchanged. This localized modification strategy allows the binding interface to be optimized for specific non-natural targets while preserving the overall simplicity and stability of the SH3 domain framework.
Solution Approach 2:
The invention changes the binding parameters of the SH3 domain by engineering specific amino acid sequences in the RT and n-Src loops. These parameter changes in loop composition and conformation enable the domain to achieve high affinity and specificity for non-natural targets that are not recognized by wild-type SH3 domains.
3Ease of operation
If antibodies are used for intracellular targets, then target accessibility is achieved, but stability and immunogenicity issues arise
Solution Approach 1:
The invention extracts the target recognition function from antibodies and implements it in a smaller, more stable SH3 domain scaffold. This extracted approach allows the binding function to operate effectively in intracellular environments where the full antibody structure would be unstable or immunogenic, while maintaining the ability to access intracellular targets.
Data Source
Figure 1a~1c
Figure 2
Figure 3a
AI summary
The present invention relates to a recombinant binding protein comprising at least one derivative of the Src homology 3 domain (SH3) of the FYN kinase, wherein at least one amino acid in or positioned up to two amino acids adjacent to the src loop and/or at least one amino acid in or positioned up to two amino acids adjacent to the RT loop is substituted, deleted or added. Furthermore, the invention is directed to fusion proteins comprising a binding protein according to the invention fused to a pharmaceutically and/or diagnostically active component. In addition, the invention concerns nucleotides coding for these binding and/or fusion proteins as well as corresponding vectors and host cells. Last but not least, the present invention relates to the use of binding and/or fusion proteins of the present invention for preparing a medicament or a diagnostic means as well as to pharmaceutical or diagnostic compositions comprising said binding and/or fusion proteins.