Peptide library is a collection of a large number of small peptides with specific length and different sequences, which includes the arrangement and combination of various (or most) amino acid sequences in the short peptides of this length.
The peptide library was first proposed by geyson and his colleagues in 1986. Here are their opinions:
① The binding or recognition between protein molecules is mainly completed by the interaction of several amino acid residues on the local peptide segment, which form a non covalent bond between these amino acids;
② Although the sequences of some peptides are different from the natural epitopes of antigens, they bind antibodies or ligands in the same way. Therefore, this polypeptide with key amino acid residues is called mimotope.
The concept of mimic epitope plays an important role in the development of random peptide library.
The genes encoding random polypeptide segments were synthesized, and then these genes were cloned into phage vector. The polypeptides were displayed on the phage surface one by one by phage epitope display technology, and a polypeptide library was constructed. During screening, peptides combined with specific targets were screened from the library according to the specific interaction between specific receptor targets and some peptides in the peptide library.
The combinatorial library is a peptide library that synthesizes thousands of peptides by random synthesis of peptides on resin. For example, the 5-peptide library will have five peptides to the 5th power, and the 9-peptide library will have nine peptides to the 9th power. Then, according to the specific interaction between the specific receptor target and some peptides in the peptide library, the peptides combined with the specific target are selected.
A peptide library composed of thousands of peptides and DNA synthesized by DNA is randomly synthesized on the carrier resin, in which each amino acid will synthesize several nucleotides to encode the information of the polypeptide. When screening, the receptor target needs to be connected with a fluorescent molecule. If a polypeptide binds to the receptor, the corresponding resin will have fluorescence. These fluorescent resins were used as templates for PCR amplification, and then sequenced to obtain the information of peptides.
Application of peptide library:
Determine the target position
Develop a vaccine
Screening of receptor ligands
Discovery of drug peptides
Interactions between proteins
Peptide nucleic acid
Screening of enzyme substrates or peptidase inhibitors
Mapping of antigen binding sites or epitopes
Discovery of T cell epitopes
Where the antibody binds to the antigen (protein)
Cross-reaction of antibodies with related proteins
Identification of short peptide antigens