Phage Display Peptide Library Platform
Based on phage display technology, Alpha Lifetech can provide customers with high-quality phage display peptide library construction and screening services including linear 7 peptide libraries, linear 9 peptide libraries, linear 10 peptide libraries, linear 15 peptide libraries, linear 12 peptide libraries, cyclic 7 peptide libraries, and other peptide libraries, library diversity, insertion rate, positive rate can reach more than 90%, to meet the different needs of various customers for phage display peptide libraries.
Phage display libraries are widely used in biomedical research and applications. For example, in antibody engineering and antibody development, phage display libraries can be used to screen and improve antibody variants; In drug screening and drug target discovery, phage display libraries can be used to search for proteins or peptides with drug potential. In vaccine research, phage display library can be used for vaccine antigen selection and vaccine development. In addition, phage display libraries can also be used in many fields such as protein interaction research, cancer diagnosis and treatment.
Phage Display Technology
Phage display technology is a technology that fuses the target protein gene with the phage surface protein gene, and makes the target protein present on the phage surface in the form of fusion protein through gene expression. These proteins displayed on the phage surface can maintain relative spatial structure and biological activity, and can be screened, detected and recognized by interacting with specific antibodies or other molecules. The display objects of phage display technology include antibody, antibody fragment, peptide segment, cDNA, etc.
The system of phage display technology mainly includes M13 phage display system (such as PⅢ display system, PⅧ display system, etc.), λ phage display system, T4 phage display system, T7 phage display system, etc. Each of these systems has its own characteristics and is suitable for different research needs. M13 phage, due to its lysogenic properties, M13 phage does not lyse the host cell after infecting it, which allows it to continuously replicate and express foreign fragments within the host cell, suitable for long-term screening and stable expression. Because of its short life cycle and high replication efficiency, T7 phage can rapidly produce a large number of progeny phages, which is suitable for high-throughput screening and rapid expression.
M13 Phage | T7 Phage | |
---|---|---|
1. Morphological Structure | Filamentous phage | Polyhedral phage |
2. Genetic Material | Circular single-stranded DNA molecule | Linear, double-stranded, terminally superfluous DNA |
3. Replication and Infection | Lysogenic phages, assembled in periplasm, can be secreted from bacterial membranes without lysing host cells. | Virulent phages, progeny of phages assembled in the bacterial cytoplasm, are released by cell membrane lysis. |
4. Display System | A display system was constructed using pIII and PVIII capsid proteins, suitable for displaying foreign peptides/proteins of different sizes. | The display system is constructed with 10B capsid protein, which does not require a secretion process and is suitable for displaying peptides/proteins that have an inhibitory effect on the secretion process. |
5. Application Advantage | It is suitable for the display and long-term screening of small molecule peptides. | It has advantages in the rapid expression and high throughput screening of macromolecular proteins. |
Phage Display Peptide Library types
Alpha Lifetech is experienced in phage display peptide library construction and screening and has a variety of peptide library types to choose from. According to the length of the peptide, it can be divided into 7 peptide libraries, 9 peptide libraries, 10 peptide libraries, 12 peptide libraries, and 15 peptide libraries. According to the spatial conformation of polypeptides, it can be divided into linear phage peptide library and cyclic phage peptide library.
Linear phage peptide library
The peptide gene is inserted into the coat protein coding region of the phage genome, usually pIII or PVIII, and is displayed as a linear straight chain. Linear linear chain peptides may degrade easily in vivo, and their binding ability and stability may be affected.
cyclic phage peptide library
The modified ring peptide will form a fixed conformation under the action of disulfide bonds or other binding bonds, which will not only greatly improve metabolic stability and bioavailability, but also better meet the binding requirements of receptor-ligand (antibody-antigen) conformation.
Phage Display Peptide Library Process
Selection of phages
M13 type phages or T7 type phages are usually selected as carriers.
phage Display Peptide Library Construction
Construct a phage vector capable of containing a foreign protein or polypeptide coding sequence, which usually includes a promoter, selective markers, and appropriate regulatory elements. The insertion of the coding sequence of a foreign protein or peptide into a phage carrier, usually by restriction enzyme cutting and ligating methods. The constructed phage vector is transformed into the host cell, allowing the phage to replicate and express foreign proteins or peptides within the cell. Phage libraries containing multiple different foreign proteins or peptides are prepared through extensive transformation and amplification.
phage display Peptide Library screening
Fix target molecules (such as proteins, receptors, or antibodies) on a solid-phase carrier. Incubate the constructed phage display peptide library with a fixed target to allow the peptides on the phage to bind to the target molecule. During this process, unbound bacteriophages are removed by washing while retaining bacteriophages that bind to the target, and high affinity bound bacteriophages are eluted. The recovered bacteriophages are amplified by infecting Escherichia coli and then subjected to the next round of screening. It usually takes 3-5 rounds of screening to obtain peptides with high binding efficiency.
Peptide design and synthesis
Synthesize peptides based on screening sites.

Fig.1 Phage display peptide library construction and screening process

Phage Display Peptide Library Construction Platform
Alpha Lifetech has a number of peptide library construction technologies. We mainly provide T7 peptide library construction service and M13 peptide library construction service according to phage types.
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Phage Display Peptide Library Screening Platform
Alpha Lifetech has rich experience in peptide phage library screening, providing strong technical support for small molecule drug discovery, clinical diagnosis,disease treatment and biological research.
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