M13 Phage Display Vectors for Longer Peptide Integration
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Solution Overview
Problem
Current phage display systems using type 33 vectors face limitations in displaying longer peptides, as they reduce phage infectivity and result in lower copy numbers, making it difficult to isolate target-specific peptides with high affinity.
Innovation Solution
Introducing defined mutations in the wild-type g.III gene of type 33 bacteriophage M13 vectors to reduce the incorporation of the polypeptide encoded by the mutated gene, thereby increasing the display of exogenous peptides up to 35 amino acids on the phage surface while maintaining phage infectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If type 33 vectors are used to display longer peptides, then peptide display capability is improved, but phage infectivity is reduced
Solution Approach 1:
The patent applies parameter changes by modifying the signal peptide sequence parameters (amino acid composition, charge distribution, hydrophobicity) to optimize the balance between peptide display capability and phage infectivity. Specific substitutions in the signal peptide sequence alter its processing efficiency and routing, enabling longer peptides to be displayed while maintaining adequate infectivity levels.
2Quantity of substance
If type 3 vectors are used to display peptides, then display copy number is increased, but peptide length is limited
Solution Approach 1:
The patent applies segmentation by dividing the single g.III gene into two separate copies (g.IIIa and g.IIIb), each capable of independent expression. This allows the system to accommodate longer peptide sequences that would be too bulky for a single gene product, while still achieving sufficient display copy numbers through the combined contribution of both gene copies.
Solution Approach 2:
The patent modifies parameters of the g.III gene copies, including signal peptide sequences and coding regions, to optimize their expression levels and functional properties. These parameter changes enable each copy to contribute effectively to peptide display while accommodating longer peptide sequences.
3Productivity
If wild-type g.III gene is used, then phage assembly is efficient, but exogenous peptide display is limited
Solution Approach 1:
The patent applies local quality by making specific localized modifications to the g.III gene sequence while preserving the overall structure and function necessary for phage assembly. The modifications are concentrated in specific regions (signal peptide, coding sequence) that control peptide display, while the rest of the protein maintains its native assembly function.
Solution Approach 2:
The patent changes parameters of the g.III gene including signal peptide sequence composition, coding region length, and amino acid composition to enable exogenous peptide display. These parameter changes are optimized to maintain sufficient phage assembly efficiency while providing the necessary capacity for displaying modified or longer peptide sequences.
Data Source
AI summary
The present invention relates to vectors suitable for use in displaying proteins on the surface of bacteriophage M13 as fusion constructs with the surface protein P.III, bacteriophage M13 particles comprising a mutated P.III protein on the phage coat surface, as well as methods for producing bacteriophage M13 particles and methods for transfecting or infecting a host cell comprising the vectors and bacteriophage of the invention.