M13 Phage Display Peptide Library Construction Platform

Alpha Lifetech has industry-leading technical capabilities in the construction platform of the M13 phage display peptide library, providing customers with high-quality and high-efficiency project services. We have a mature peptide synthesis platform, which can synthesize high-purity and diversified functional peptides. Using advanced M13 phage display technology, we can accurately screen the target peptide sequence, significantly improve the screening efficiency and hit rate, and provide personalized solutions for complex project requirements. Alpha Lifetech helps customers quickly advance the project's progress and achieve innovative breakthroughs in scientific research and industrialization.

M13 phage is a filamentous phage. Its genome is single-stranded DNA, which can encode shell proteins ( such as pIII and pVIII ). By inserting exogenous DNA into the coding region of these proteins by genetic engineering, the target polypeptide can be displayed on the phage surface. The core of the M13 phage display technology is to combine the random peptide sequence with the phage capsid protein and display it on the surface of the phage for functional screening.

The basic characteristics of M13 phage

Type

M13 phage belongs to filamentous phage and does not have the ability to lyse host cells.

Genome

Single-stranded DNA, about 6.4 kb.

Structure

M13 phage has a filamentous shell, which is composed of a major capsid protein ( pVIII ) and a small number of capsid proteins ( pIII, pVI, pVII and pIX ).

Display characteristics

Coat proteins ( mainly pIII and pVIII ) can be used to display exogenous peptides or proteins.

M13 Phage Display Peptide Library Construction Process

Combining peptide synthesis and phage display technology, the construction process of peptide library includes the following steps:

Design and insertion of polypeptide coding sequence

Peptide sequences were designed by chemical or bioinformatics methods according to requirements.

Randomized or directed evolution peptide genes were inserted into the M13 phage coat protein gene ( such as pIII or pVIII ).

At this stage, solid phase peptide synthesis or liquid phase peptide synthesis can be used to verify the functional characteristics of candidate sequences.

Construction of phage peptide library

The vector was transformed into E.coli host cells and infected with helper phages ( such as M13KO7 ) to generate chimeric phage particles.

A high concentration and diverse phage peptide library was obtained by amplification to achieve efficient M13 phage display.

Screening and optimization

The target molecules ( such as antibodies and receptors ) were used for multiple rounds of biological elutriation to screen phage particles that were highly bound to the target.

The biological activity of the selected peptide sequence was further verified by peptide synthesis techniques ( such as solid phase peptide synthesis or liquid phase peptide synthesis ).

Fig.1 Schematic overview of library construction, ORF selection, panning on captured serum antibodies and validation of the immunogenic character. ( Reference source: Oligopeptide m13 phage display in pathogen research.)

Construction of m13 Phage Peptide Library Workflow

Process	Service Content	Timeline
1. Select A Phage Vector	Select suitable M13 phage vectors, which typically contain promoters, selective markers, and appropriate regulatory elements.	/
2. DNA Fragment for Designing and Synthesizing Random Peptides	Depending on the study goal, the sequence of random polypeptides is designed, usually between 6 and 20 amino acids in length. The oligonucleotide fragments of these peptides were synthesized randomly by chemical synthesis method.	1 week
3. Insert A DNA Fragment of A Random Polypeptide Into A Phage Vector	DNA fragments of phage vectors and random polypeptides are cut using restriction enzymes to produce complementary sticky ends. The recombinant phage vector is formed by connecting the DNA fragments of random polypeptides with the phage vector by DNA ligase.	1 day
4. Transforming Host Bacteria	Transformation of recombinant phage vectors into host bacteria, such as E. coli. The phage vector was successfully replicated and expressed in bacteria by means of transformation methods such as electric transformation or heat shock.	1 week
5. Amplification and Screening of Phages	The host bacteria were amplified in selective media to produce a large number of recombinant phages. The phage was extracted and purified by centrifugation and filtration, and the high concentration peptide library was obtained. Affinity screening of target molecules (such as antibodies, receptor proteins, etc.) is used to screen phage clones that can bind to target molecules with high affinity from peptide libraries.	1 week