Phage Display Library Construction
Phage display is a powerful method for presenting peptides, proteins, or antibodies on the surface of filamentous bacteriophages, allowing for high-throughput selection of target-specific binders from large libraries. VectorBuilder specializes in creating high-quality phage display libraries including small peptide libraries and antibody display libraries, empowering your drug discovery, vaccine development, and protein-protein interaction studies.
Highlights
Construction of a variety of synthetic or native phage display libraries, including peptide, VHH, Fab, and scFv display libraries.
High-complexity (109-1010) and high-uniformity libraries with NGS validation.
High-titer (>1013 PFU/ml) phage libraries.
Streamlined with antibody screening services using our proprietary high-throughput affinity measurement approach.
Service Details
Price and turnaround Price Match
| Service Module | Brief Description | Price (USD) | Turnaround |
|---|---|---|---|
| Library design | Our process starts with a consultation where our experts will help design the right library for your needs. We can guide you through the library design for the peptides, proteins, or antibodies of interest. | Free | 1-3 days |
| Variant sequences preparation | Variants can be de novo synthesized or sourced from naive or immunized animals. | Please inquire | |
| Phage library construction |
We conduct massive parallel cloning of the variant sequences into the desired backbone (phage vector or phagemid vector). Plasmid library quality is preliminarily assessed by Sanger sequencing. After phage assembly (with or without helper phage) and efficient amplification, the high-titer phage library (>1013 PFU/ml) is shipped with dry ice to your bench or proceeded to downstream screening experiments. |
Please inquire | 3-5 weeks* |
| NGS validation | We offer NGS validation of constructed libraries, allowing for evaluation of library complexity and uniformity. | Please inquire | 1-3 weeks |
| Library screening | We offer VHH antibody discovery using sequence-guided screening of alpaca-derived libraries, as well as downstream characterization and optimization. | Please inquire | |
* The above turnaround time information is for constructing libraries with a complexity of 109. For the construction of libraries with ultrahigh complexity (e.g. 1010), an additional 1-2 weeks are required.
Technical Information
At VectorBuilder, we can construct both short peptide display libraries and antibody display libraries (e.g. VHH, Fab, scFv). The two types of libraries differ in size and complexity of the displayed molecule, vector backbone, and phage assembly method.
Source of variants
The to-be-displayed variants can be obtained either through de novo synthesis or from naive or immunized animals. The table below summarizes the key characteristics of each source:
| Library Type by Source | Description | Key Features | Advantages |
|---|---|---|---|
| Naive library | B cells are isolated from unimmunized, healthy animals, and antibody sequences are specifically PCR amplified from the cDNA. |
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| Immunized library | B cells are sourced from immunized animals that are previously exposed to specific antigens, and antibody sequences are specifically PCR amplified from the cDNA. |
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| De novo synthesized library | Entirely synthetic; can be defined sequences or sequences containing degenerate nucleotides |
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Library backbone
Another key distinction between the two types of phage display libraries is the choice of the vector backbone.
M13 phage vector for peptide display
Bacterophage-derived vectors such as M13KE phage vectors are typically used for short peptide display (up to 50 amino acids). The M13 phage DNA contains the entire phage genome in single-stranded DNA, in which about half of the genes encode coat proteins (G3P, G6P, G7P, G8P, and G9P) while the others are essential for genome replication, phage assembly, and extrusion (Figure 1A).
Figure 1. (A) Map of the M13KE vector. (B) Recombinant phage displaying short peptide on the surface.
The peptide of interest is fused to the phage coat protein G3P, forming a hybrid fusion protein that is displayed on the phage surface. This linkage of the recombinant peptide and phage coat protein enables the peptide to be displayed on the surface of the phage, making it accessible for binding assays and an effective system for identifying high-affinity binders (Figure 1B). The vectors are then introduced into host E. coli cells to achieve assembly and amplification of the recombinant phage particles to generate a high-titer phage library. Because the phage vectors contain the entire phage genome, they can produce fully functional phage particles without the need for helper phages.
Phagemid vector for antibody display
Phagemid vectors like pComb3x are commonly used for antibody display libraries (Figure 2A). The pComb3x phagemid contains a gene for a phage coat protein, such as G3P, which is fused to the foreign DNA sequence, enabling the surface display of antibody fragments or full-length antibodies (Figure 2B). However, the phagemid lacks the structural and replication genes needed for phage assembly, and hence, is unable to produce phage particles on its own. A helper phage is required to provide the missing phage genes, allowing the packaging of recombinant phage particles to be secreted.
Figure 2. (A) Map of the pComb3x phagemid vector. (B) Recombinant phage displaying antibody on its surface.
How to Order
Customer-supplied materials
If the customer-supplied materials are needed, please send us the materials following the Materials Submission Guidelines. Please strictly follow our guidelines to set up shipment to avoid any delay or damage of materials. All customer-supplied materials undergo mandatory QC by VectorBuilder which may incur a surcharge for each item. Please note that production may not be initiated until customer-supplied materials pass QC. For customer-supplied premade plasmid pools, we cannot provide any guarantees regarding the complexity or uniformity of the library.
Resources
Documents
Flyers
FAQ
These libraries are made with the M13KE vector in which the entire phage genome is present. Therefore, all G3Ps on each phage are fused with mono or multivalent peptides, which adds to the structural and functional constraints of the phage system. We recommend the peptides displayed are below 25 amino acids. Peptides or proteins larger than 50 amino acids increase the size of the fusion protein, which can interfere with the phage’s ability to infect E. coli efficiently, thus affecting the propagation and screening of phages in the library.
Shorter peptides provide significant advantages in phage display libraries, including easier synthesis and expression, which reduces production complexity. Additionally, shorter peptides are ideal for high-affinity binding assays and therapeutic development, as they can be engineered for specificity while maintaining stability and functionality. These qualities make them highly effective for applications like ligand discovery, receptor studies, and therapeutic target validation.