A peptide library is a collection of a large number of small peptides with a specific length and different sequences, which includes the permutation and combination of various (or most) amino acid sequences in the short peptides of this length. The peptide library was first proposed by Geyson et al. in 1986. They believed that the binding or recognition between protein molecules is mainly completed by the interaction between several amino acid residues on the local peptide segment, and these amino acids form non-binding molecules; some polypeptides, although their sequences are different from the natural epitope of the antigen, bind the antibody or ligand in the same way, so this polypeptide with key amino acid residues is called a mimotope. The concept of mimotopes played an important driving role in 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.
1. Custom peptide libraries based on known structures
Based on the structure of the known compound, a series of polypeptides are constructed and designed in the following ways, including but not limited to, and screened for the function and indication of the target compound, in order to obtain new molecules or new structures with the target efficacy. N-terminal, C-terminal, side chain modifications: acylation, esterification, PEGylation, beta-amino acid substitution, D amino acid substitution, backbone amino methylation, disulfide bond substitution, conformational locking (helix, beta-sheet), mirror peptide, cyclic peptide (head-to-tail cyclization, side chain cyclization), special molecular markers, hydroxy acid substitution.
2. Phage display peptide library
Artificially synthesize genes encoding random polypeptide segments, then clone these genes into phage vectors, and display the polypeptides one by one on the phage surface through phage epitope display technology to construct a polypeptide library. During screening, according to the specific interaction between a specific receptor target and some polypeptides in the peptide library, the polypeptides that bind to the specific target are screened from the library.
3. One-strain-one-species chemical combinatorial peptide library
Combinatorial libraries are peptide libraries that synthesize tens of thousands of peptides at a time by randomly synthesizing peptides on resin. For example, a 5-peptide library would have 55 pentapeptides, and a 9-peptide library would have 99 nonapeptides. Then, during screening, according to the specific interaction between the specific receptor target and some polypeptides in the peptide library, the polypeptides that bind to the specific target are screened out.