12 Phage Display Peptide Library Screening Service

The phage display platform provided by KMD Bioscience is an ultra-high throughput ligand screening method. The phage display platform can construct up to 1013/ml peptides or antibody clones displayed on phage. After subsequent rounds of biopanning, KMD Bioscience can provide up to 105 validated peptide or antibody sequences, providing a solid research foundation for searches of subsequent enzyme substrate, protein ligand and high-specificity antibody. Based on the phage display platform, KMD Bioscience can build 7 peptide library, 12 peptide library and cyclic 7 peptide library, etc. for customers.


Applications of 12 Phage Display Peptide Library:


To elucidate the physiological functions of hyaluronic acid (HA) from a family of cell-surface glycosaminoglycans, The study used purified HA to biopan a 12-phage display peptide library. The predominant peptide screened, Pep1, can bind to free HA, HA expressed on the cell surface and prevented binding of HA to the HA receptor (CD44) expressed on the cell surface. Correlative studies of this activity of Pep1 demonstrate that HA plays a role in leukocyte migration in inflamed tissues. Miraculously, Pep1 prevented contact dermatitis when applied to the skin and then exposed to a known allergen, demonstrating a link between HA and immune responses to skin irritants with broad clinical implications.

The discovery of a peptide based on the 12 phage display peptide library laid the foundation for the development of a multivalent inhibitor of anthrax toxin that virtually eliminated anthrax toxicity in rats. The structural domain of anthrax protective antigen (PA) with a heptameric structure was immobilized and the 12 peptide library was panned. Peptides specifically bound to inactive, unassembled PA was removed using soluble PA monomer washes, and specifically bound peptides were competitively eluted with soluble heptameric PA. Although the resulting peptides were specific for the toxic heptamer PA, the binding was weak, and tetramerization of the peptides on the soluble scaffold improved the binding affinity.


Construction of the 12 Phage Display Peptide Library:


The 12 phage display peptide library can thus be thought of as having the equivalent diversity of the 7 library, but spread out over 12 residues. In both the 7 and the 12 phage display peptide libraries, the first residue of the peptide-pIII fusion is the first randomized position, while the first randomized position in the C7C library is preceded by Ala-Cys. All of the libraries contain a short linker sequence between the displayed peptide and pIII: Gly-Gly-Gly-Ser.

Random oligonucleotide fragments of the 12-mer peptide were synthesized by chemical synthesis and then inserted into the gene encoding the shell protein of the phage vector and transformed into E. coli by genetic engineering recombinant technology. A random 12-mer peptide was fused to the M13 phage minor coat protein (pIII) to form a combinatorial library. The proliferated and generated phages carry exogenous peptides on their surface, and each phage expresses one exogenous peptide on its surface. All these phages constitute a prefabricated random 12 peptide library.

The target molecule provided by the customer is used to obtain a phage clone that can bind to the target molecule with high affinity after a screening, amplification and selection step from the whole prefabricated phage random 12 peptide library. By determining the DNA sequence of this phage, the amino acid sequence of the peptide carried by the phage can be known.


Phage Display Peptide Library Screening:


Phage display describes a selection technique in which a library of peptide or protein variants is expressed on the outside of a phage virion, while the genetic material encoding each variant resides on the inside. This creates a physical linkage between each variant protein sequence and the DNA encoding it, which allows rapid partitioning based on binding affinity to a given target molecule (antibodies, enzymes, cell-surface receptors, etc.) by an in vitro selection process called panning. In its simplest form, panning is carried out by incubating a library of phage-displayed peptides on a plate (or bead) coated with the target, washing away the unbound phage, and eluting the specifically bound phage (Fig 1). The eluted phages are then amplified and taken through additional binding/amplification cycles to enrich the pool in favor of binding sequences. After 3-4 rounds, individual clones are characterized by DNA sequencing and binding assays.



Fig 1 Phage display peptide library screening


12 Phage Display Peptide Library Screening Service Process:


Services Available

Service Content


Support Multiple Provision Forms

-Purified protein

-Unpurified protein (provides purification services)

-Targeted targets


Quality Control of Antigens

Antigen purity testing by SDS-PAGE

3 days

Peptide Library Screening

Positive clones recognizing antigen by 3-4 rounds of screening

2 weeks

Antibody Sequencing

Positive clone sequencing

1-2 week

Antibody Quality Control

Expression of target antibody in E.coli, followed by quality control by Elisa

1 week


Experimental report and

 >10 independent peptide clones

Depends on express


Advantage of Service:


-Applications in immunology, proteomics and medicine discovery.

-Pre-made phage display peptide library constructed by KMD Bioscience for high throughput production.

-Accurate and fast experimental process, saving time for customers.

-Have professional technical experts to control the screening process accurately.

-Screening a large number of different clones without immunogenicity problems.

-Peptide screening is high specificity and high sensitivity.

-Widely used in the development of peptide medicines and accurate localization of antigenic determinants.

-Rapid production capability of soluble antigen: combined with our existing recombinant protein expression systems, we can produce high purity and high biological activity soluble antigens to support immunization or screening of target molecules.


How to Order?

If you have any questions regarding our services or products, please feel free to contact us by E-mail: info@kmdbioscience.com or Tel: +86-400-621-6806;