Screening Strategies for Cyclic Peptide Drugs-Special Topic on Phage Display Technology-Tekbiotech-Yeast Display Service,Phage display technology

Screening Strategies for Cyclic Peptide Drugs

Cyclic peptides are a type of polypeptide chain composed of amino acids, which are connected to each other to form a ring structure. The shapes, sizes and chemical compositions of cyclic peptides in nature are different, but they have common characteristics: 1. They have certain biological activities, and they themselves or their derivatives are used to treat diseases; 2. They are applied in the field of biomolecules and can be used as probes for selective regulation of target proteins or high-affinity ligands.

Cyclic peptides are widely used in the medical field, such as oxytocin, vasopressin, antibiotics, etc. They can be used for drug development based on their own structural stability, specificity, binding force, affinity, and proteolytic stability are higher than linear substances, and they can also increase membrane permeability. Therefore, as an important part of the development of a new generation of drugs, cyclic peptides have very broad prospects in treatment.

Due to the complex structure of polypeptides, the synthesis of cyclic peptides is very difficult. The cyclization method of natural polypeptides greatly limits the development of new cyclic peptide drugs. Therefore, it is urgent to develop new natural polypeptide cyclization strategies to provide solutions for the construction and high-throughput screening of cyclic peptide libraries.

Among the current methods for screening and generating polypeptide libraries, phage display and mRNA display technologies are more widely used.

1. Phage Display Technology

Phage display has the advantages of mature research system, low cost, and a short list of operating rooms. The use of this technology to develop cyclic peptide drugs can provide a new strategy for the screening of cyclic peptide drugs.

The construction of phage display cyclic peptide library is to display peptides and proteins on the pⅢ or pVⅢ protein of M13 filamentous phage, which is suitable for screening cyclic peptide ligands with high affinity for specific targets. Among them, bicyclic peptides have a more complex and stable structure and are developed for the treatment of tumors. Bicyclic peptide-drug conjugates have been generated and are being evaluated in clinical trials.

Types of phage cyclic peptide library screening: in vivo screening and in vitro screening. The more commonly used in vitro screening is divided into solid phase screening and liquid phase screening according to the fixation method of the target protein. Solid phase antigen screening enriches proteins through 3-4 rounds of elution to obtain phage display library; liquid phase antigen screening uses magnetic beads to capture bound phages by incubating biotin-labeled target proteins. Solid phase screening consumes more protein, and the natural epitope of the protein will be destroyed. Liquid phase screening has the characteristics of high efficiency and high enrichment. The method of phage library screening depends on the specific experimental requirements, which will have a certain impact on the effect of the phage cyclic peptide library.

Case display: 1. Andersen et al. screened the phage display single cyclic peptide library for mouse uPA. After four rounds of iterative screening, they finally isolated the high affinity sequence CPAYSRYLDC, which may become a useful probe molecule in the tumor invasion and metastasis model. 2. Huang et al. constructed 6 phage display cyclic peptide libraries to screen ACE2 inhibitors through MANP, a derivative of the M13mp18 phage vector, which can effectively inhibit the enzyme activity of ACE2 on the natural substrate decapeptide angiotensin I (AngI) and the synthetic substrate M-2195. 3. Song L et al. used phage screening technology to screen 7 cyclic peptide phage libraries containing random residues, identified the activity of cyclic peptides, and provided a research basis for studying effective peptides for protein-protein interactions.

2. mRNA Display Technology

As an emerging in vitro peptide screening technology, mRNA display technology is based on the principle that peptides are covalently linked to their encoding mRNA during ribosome translation.

In contrast to phage display, due to the limitation of DNA conversion during library construction, the size of the library is limited to billions of peptides, and mRNA display technology has a larger library. However, this technology is limited by the screening environment without ribonucleases.

Case display: 1. Suga et al. used this technology to effectively combine structurally diverse non-natural amino acids (amino acids containing chloroacetamide groups) with cysteine to form a cyclization. 2. The cyclic peptides prepared by Suga et al. using this technology can allow methylated amino acids to permeate through the membrane. 3. Chugai Pharmaceutical et al. developed a new mRNA display method that can effectively bind a large number of methylated amino acids, thereby preparing cyclic peptide inhibitors that act on tumor targets.

TekBiotech has been committed to the field of antibodies for many years, has rich experience and mature technology, and can provide customers with high-quality phage display technology, mRNA display technology, nano-antibody humanization services, and humanized monoclonal antibody preparation services. In addition, TekBiotech has many years of experience in phage cyclic peptide library screening and can provide peptide library screening services, phage library screening services, and customized antibody services, including antibody expression and purification, affinity determination, antibody sequencing, etc., to meet customer needs.

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