In 1985, Smith et al. genetically engineered an exogenous peptide sequence to be displayed on the surface of filamentous phages. In 1988, they cloned the synthesized oligonucleotide fragments with random sequences into filamentous phages. One kind of peptide was displayed on the surface of each phage particle after the expression, and all of these phages displaying different peptides constituted a phage display peptide library. Then, phage display peptides that bind to the specific proteins were obtained by screening. From these peptides, the binding peptides that bind to specific proteins were screened. Peptide libraries are a powerful screening tool in biology and chemistry. It can be used to screen a very small number of peptides from a large number of peptides with critical biological activities. Currently, peptide libraries are widely used in proteomics and related fields, including but not limited to drug discovery, protein-protein interactions, antigenic epitope screening, GPCR ligand screening, protein function analysis, enzyme substrate or inhibitor screening, messenger molecule discovery, and peptide/protein signaling. Based on our rich field experience and advanced research platform, Creative Biolabs provides comprehensive services to support premade antibody library screening and premade phage display peptide library screening.

Premade Phage Display Peptide Library

A peptide library is a large collection of small peptides of a specific length with different sequences, which includes various (or most of them) amino acid sequences of a short peptide of that length in a permutation. Some peptides have different sequences from the natural epitopes of antigens but bind antibodies or ligands in the same way, so such peptides with key amino acid residues are called mimotopes. The concept of mimetic epitopes has played an important role in driving the development of peptide libraries. Peptide libraries can provide powerful tools for drug design, protein-protein interactions, and other biochemical and pharmaceutical research and applications.

Phage peptide library technology is actually a technology that combines gene expression products with affinity screening by displaying all exogenous peptides of a certain length on the surface of phage vectors through phage display technology. Using phage as a carrier, a specific length of randomly synthesized gene fragment is inserted into the gene coding for the N-terminal end of phage shell proteins (e.g., pIII and pⅧ), so that the corresponding exogenous polypeptide coded for by this gene is expressed at the N-terminal end of phage shell proteins in the form of fusion proteins and is displayed on the surface of phage particles. The exogenous polypeptide inserted in this way does not affect or disturb the phage's life cycle and, at the same time, maintains its natural conformation and can be recognized by target molecules such as corresponding antibodies or receptors. At the same time, since the gene of this specific length is randomly synthesized, theoretically, the corresponding peptide encoded by this gene should contain all the sequences of peptides of this length in nature, which constitutes a peptide library of this specific length, and the library capacity is very large.

Premade Phage Display and Peptide Library Screening

The screening principle of phage peptide library is based on the in vitro screening method of "biopanning". Common methods for screening phage peptide libraries include in situ peptide discovery at the molecular level, cell-selective peptide discovery, and overall peptide discovery. In situ peptide discovery involves encapsulating specific target proteins in a 96-well plate, which makes the peptide screening process less susceptible to interference by non-specific factors because only a single target is exposed. Cell-selective peptide discovery involves using normal cells as a control to screen out active peptides with high affinity for cancer cells. These peptides tend to bind to components or surface receptors that are highly expressed by tumor cells and thus have a certain degree of tumor targeting. The overall peptide discovery is performed by injecting the peptide phage library intravenously into the animal, extracting phage from the subcutaneous tumor tissue, and amplifying it. After 3~5 rounds of repeated biopurification, the phage that binds specifically to tumor tissue increases significantly, and the targeted peptides are obtained after enrichment. A variety of tumor-binding peptides have been screened by this method. In addition, disease-specific peptide discovery is an important screening method.

Premade phage display peptide library screening technology is widely used for antigenic epitope studies, immunodiagnostic studies, gene vaccine studies, and drug screening and development. For example, this application can be used for particulate matter binding peptide identification and soft matter binding peptide identification.

Creative Biolabs has a wealth of knowledge and experience in premade antibody library screening. We would be happy to share with you our knowledge and experience in premade phage displayed human antibody library construction and premade phage display peptide library screening.

All listed services and products are For Research Use Only. Do Not use in any diagnostic or therapeutic applications.