Engineered Antibody CDR Loops for Phosphotyrosine Detection
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Solution Overview
Problem
Current antibodies for detecting phosphorylated tyrosine (pY) lack sensitivity and specificity, and the structural mechanism of pY recognition remains unknown, limiting their performance in applications such as Western blot and immunofluorescence.
Innovation Solution
Development of novel antibody CDR sequences that improve pY binding affinity by leveraging the conserved structural features of pan-specific pY antibodies PY20 and 4G10, optimized through computational design and phage display selection, creating enhanced CDR sequences for improved pY binding compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional antibodies are used for pY detection, then the detection can be performed, but the sensitivity and specificity are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the CDR sequences of antibodies to optimize their binding parameters. Specifically, the CDR3 heavy chain sequence was mutated from TYG to TSG, and CDR3 light chain was mutated from SSY to SSV, resulting in improved binding affinity and specificity for phosphotyrosine residues
Solution Approach 2:
The patent applies local quality by making specific localized changes to the CDR regions of the antibody while maintaining the overall antibody structure. The mutations are confined to specific positions in the CDR3 regions of both heavy and light chains, allowing optimization of local binding properties without affecting global stability
2Reliability
If structure-guided mutagenesis is applied to improve binding affinity, then pY binding affinity improves, but the structural mechanism understanding is still lacking
Solution Approach 1:
The patent applies preliminary action by determining the crystal structure of the antibody-pY complex before performing mutagenesis. The structural information obtained from X-ray crystallography at 2.1 Å resolution provided a roadmap for rational design of mutations in the CDR regions, enabling targeted improvements in binding affinity
3Adaptability or versatility
If pan-specific pY antibodies are used, then broad pY detection is achieved, but sequence specificity is reduced
Solution Approach 1:
The patent applies local quality by introducing specific mutations in the CDR3 regions that enhance sequence specificity while preserving pan-specific capability. The mutations create local chemical environments that favor binding to phosphotyrosine while maintaining tolerance for sequence variation through the conserved phosphate-binding motif
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 novel CDR sequences result in antibodies with superior pY binding affinity and specificity, enhancing their performance in Western blot and immunofluorescence applications, allowing for more effective detection and isolation of pY-containing proteins.
Implementation Method 1
Both structures host a deeply buried cationic binding site for the phosphate group that provides multiple hydrogen bonds and salt bridges from the same residues in the antibodies
Implementation Method 2
Both structures host a deeply buried cationic binding site for the phosphate group that provides multiple hydrogen bonds and salt bridges
Data Source
AI summary
Presented herein are novel phosphotyrosine binding compositions, including antibodies and antibody fragments. The inventors of the present disclosure have resolved the crystal structures of two widely utilized pan-specific pY antibodies, PY20 and 4G10. These two known antibodies, although developed independently from animal immunizations, have surprisingly similar modes of recognition of the phosphate group, and revealed a generic binding structure among pan-specific pY antibodies. Based on this newly discovered convergent structure, engineered CDR-L3 loops were developed that impart greatly improved affinity to pY binding antibodies and other pY binding compositions. The inventions disclosed herein include antibodies and antibody fragments bearing these novel CDR-L3 sequences and methods of using such pY binding compositions for the detection of phosphotyrosine-bearing proteins.