Screening Strategies for Cyclic Peptide Drugs
* Please kindly note that our products and services can only be used to support research purposes (Not for clinical use).
Online Inquiry
The discovery of insulin a century ago forever changed the field of cyclic peptide drug research. Insulin can be said to be what millions of people with diabetes rely upon today as one of the most influential of drugs, it is a highly complex cyclic peptide hormone, through multiple disulfide bonds together.
The rigidity of cyclic peptides can improve their absorbed pharmacokinetic and pharmacodynamic properties and have a significant impact on their ability to passively permeate membranes to reach intracellular targets. For example, many cyclosporins, which are small cyclic peptides derived from fungi and used to treat a variety of diseases, exhibit "discolor" flexibility in that they can switch between several different conformations. This unique property is characteristic of the passive membrane permeability that leads to their very high, and major work has focused on understanding the fundamentals to generalize these properties in cyclic peptides.
Screening Strategies for Cyclic Peptide Drugs
Cyclic peptides are also one of the most diverse architectures in current drug discovery efforts. Their size, stability, and ease of synthesis provide attractive scaffolds for engaging and modulating some of the most challenging targets, including protein-protein interactions and those considered "undruggable". Cyclic peptide libraries are generated by means of a variety of sophisticated screening techniques, including phage display, mRNA display, resolution of peptide and protein ring ligation, and structural oriented design.
George P. Smith founded phage display in 1985 and won the Nobel Prize in chemistry in 2018. In his article, it was shown that peptides can be displayed on the outside of phages, which are viruses that infect bacteria, while the genetic information encoding them is retained on the inside of the virus.
In recent years, many laboratories have developed cyclic peptide libraries containing unique closed-loop chemistry, the introduction of nonclassical amino acids, and pharmacophore coupling.
Derda laboratory has expanded the scope based on the technology of phage cyclization of cysteine, to generate large amounts of photoelectric switch and sugar peptide library. Recently, Derda revised its cyclization chemistry laboratory, to install the unnatural pharmacophore, and use Knorr pyrazole chemical targeted carbonic anhydrase (CA), which is responsible for the catalytic conversion of the enzymes needed between carbon dioxide and water.
The Fasan laboratory established a novel strategy for cyclizing peptide on phage by using amber stop codon technology to introduce O-(2-bromoethyl)-tyrosine that can spontaneously react with a proximal cysteine residue after translation to form an irreversibility thioether bond.
The Bogyo laboratory introduced an elegant unbiased phage display screening strategy to identify irreversible covalent inhibitors of protein targets. By adding cysteine reactive vinyl sulphone or through oxime serine reactive diphenyl phosphonic acid ester warhead with 1, 3-dichloroacetone (DCA) connection, cyclic peptide library can by DCA modified warhead with the library of two cysteine residues reaction.
Example of Phage display library. (Li X et al.)
mRNA Display
mRNA display is another effective in vitro screening method. Integration of non-standard random peptides found that (RaPID) consists of Suga laboratory in 2006 to promote an mRNA display method spread. This unique strategy takes advantage of flexible tRNA synthetases that allow a variety of unnatural amino acids to be bound, including D-amino acids, N-methyl amino acids, and β-amino acids, thus significantly increasing the chemical space for screening. In addition, the genetic code reprogramming of the N-terminal formyl Met can be replaced by amino acids such as N-chloroacetyl-L-Tyr to spontaneously cyclize with the proximal cysteine residue, generating a cyclic peptide library. Recently, the Suga laboratory used the RaPID system to perform potent and selective inhibitors of the catalytic domain of factor XIIa (FXIIa), an important target for the development of antithrombotic drugs.
Overview of mRNA display to identify inhibitors of FXIIa and K-Ras (G12D). (Li X et al.)
Protein Peptide and Protein Split Ring Connection
SICLOPPS, an innovative technique, harnesses the unique function of inteins within cyclic peptides to form protein-peptide and protein split ring connections. Interns are protein domains capable of self-excising from their host protein structure, facilitating the splicing of protein fragments. In SICLOPPS, the cyclic peptide of interest is strategically inserted between split endopeptides as IC−X−IN, with "X" representing the specific cyclic peptide sequence. During translation, these two intronic fragments autonomously bind together, leading to the excision of the cyclic peptide sequence located between them. This process results in the release of the cyclic peptide with its native amide bond intact, allowing for the formation of desired protein connections. This technique offers a precise and efficient method for constructing protein-peptide and protein split ring connections, with potential applications in various fields such as biotechnology and drug development.
Overview of the SICLOPPS mechanism and hit identified to inhibit the HIF-1α/HIF-1β protein−protein interaction. (Li X et al.)
Structural Oriented Design
In recent studies from Grossmann's laboratory, inhibitors of cyclic peptides were designed to mimic the β-sheet properties of Ecadherin to develop inhibitors of the interaction between Tcf4 and β-catenin. β-catenin is a kind of auxiliary activation factor and also is the key component of Wnt signaling pathways. Excessive activation of this specific oncogenic target leads to a variety of cancers, making it an anatomical target for therapeutic intervention. Using previously published crystal structures, cyclic peptides with residues that have features of inducing β-sheets and mimic the E-cadherin binding mode were synthesized. In vitro, a fluorescence polarization (FP) assay was used to determine the binding constants of cyclic peptides. In this assay, competitive binding is detected by the change in fluorescence polarization that occurs when the fluorescently labeled Tcf4 ligand is displaced from β-catenin by a competing ligand. They are in the original design of the best big ring 12, which shows IC50 = 16μM.
Screening Technology at Creative Peptides
| Services | Description |
|---|
| Peptide Drug Screening Service | Peptide drug screening services leverage high-throughput screening platforms, computational modeling, and advanced analytical techniques to expedite the discovery and optimization of peptide-based therapeutics. These services are instrumental in accelerating the drug development process, reducing costs, and ultimately, bringing novel peptide drugs to market. |
| Peptide Library Construction and Screening | Peptide library construction and screening is a method used in drug discovery and development to identify potential therapeutic peptides. In this process, diverse collections of peptides are synthesized and systematically screened to find molecules with desired biological activities. The method involves the design and synthesis of peptide libraries, followed by the screening of these libraries against specific targets of interest. Through this approach, researchers can explore a wide range of peptide sequences and identify lead candidates with promising therapeutic properties, paving the way for the development of novel peptide-based drugs. |
| Phage Display Peptide Library Screening | Phage display peptide library screening is a technique that harnesses the power of bacteriophages to identify peptides with specific binding abilities. By presenting a diverse array of peptides on the surface of phage particles, this method allows for the selection of peptides that bind to target molecules of interest. It serves as a valuable tool in drug discovery, enabling the identification of lead compounds for the development of therapeutic agents or diagnostic tools. |
| Peptide Library Design | Peptide library design involves the strategic creation of diverse collections of peptide sequences tailored for specific research or screening purposes. It typically considers factors such as target protein structure, function, and binding sites, as well as potential post-translational modifications and structural constraints. The aim is to generate a comprehensive sampling of peptide variants to explore a wide range of interactions and identify candidates with desired properties, making it a crucial step in peptide-based drug discovery and biomolecular research. |
Challenge of Developing Cyclic Peptide
Developing cyclic peptide drugs presents a multifaceted challenge in screening strategies due to the intricate three-dimensional structure of these peptides, which includes multiple disulfide bonds and diverse amino acid sequences. Detecting their desired biological activities, such as anticancer or antimicrobial properties, requires sensitive assays capable of discerning subtle differences in activity among cyclic peptide variants. Additionally, the stability and bioavailability of cyclic peptides must be evaluated, alongside the risk of off-target effects, to ensure their efficacy and safety as therapeutic agents. Overcoming these hurdles demands innovative approaches at the intersection of peptide chemistry, structural biology, pharmacology, and drug delivery, leveraging advancements in screening technologies to expedite the discovery and optimization of cyclic peptide drugs for clinical use.
Conclusion
In conclusion, addressing various challenges requires interdisciplinary approaches combining expertise in peptide chemistry, structural biology, pharmacology, and drug delivery. Advances in screening technologies, such as computational modeling, high-resolution imaging, and microfluidics, are helping to overcome these challenges and accelerate the discovery and development of cyclic peptide drugs with therapeutic potential. This ongoing research paves the way for innovative therapeutics and improved health outcomes, marking a significant milestone in medical science's quest for effective treatments.
Reference
- Li X, Craven T W, Levine P M. Cyclic peptide Screening Methods for Preclinical Drug Discovery: Miniperspective[J]. Journal of Medicinal Chemistry, 2022, 65(18): 11913-11926.
