7-mer Peptide Library Synthesis

Chemically synthesized randomized oligonucleotide fragments encoding cyclic heptapeptides

3-5 weeks

7-mer Peptide Library Construction Service

pMECS-based target gene homologous recombination assembly, TGI transfomation, and M13 phage display 7-mer library construction

4-6 weeks

7-mer Peptide Library Screening Service

Three rounds of biopanning (KMD Bioscience will determine if additional rounds are necessary under special circumstances, at no extra cost). 50-80 blue plaques are picked for DNA sequencing

4-5 weeks

Extracellular Domain (ECD) of Membrane Receptors

Using isolated full-length membrane receptors as targets in vitro for library screening is challenging due to their high hydrophobicity; they maintain native folding only within a lipid bilayer environment. Membrane receptors typically possess large, multi-domain extracellular regions that may interact with diverse peptide sequences. Isolated ligand-binding domains of receptors serve as excellent alternative targets for focused selection of peptides mimicking endogenous ligands. Targeting shorter receptor fragments can also enhance specific toward particular members of highly conseved receptor families. Moreover, synthetic peptides corresponding to specific receptor domains may adopt confomations distinct from the native protein. Consequently, selected peptides might not recognize the receptor in its natural context. Therefore, it is necessary to first screen the Phage Display Library against the synthetic peptide, followed by affinity selection of the resulting enriched library against the native protein.

Neutralizing Antibodies Targeting Endogenous Binding Partners

Neutralizing antibodies against endogenous ligands can serve as surrogate targets for indentifying biologically active peptides. The antigen-binding region of an antibody mimics the receptor's ligand-binding site, providing a "mold" for recovering peptides that cross-react with the receptor. While neutralizing antibodies may not recognize the exact receptor-binding epitope on the ligand, they exert antagonism by sterically blocking ligand-receptor interactions through binding to sites adjacent to these regions.

Whole-Cell Screening

The Phage Display Library can also be screened against live cells expressing the membrane receptor of interest. This eliminates concerns about target protein misfolding and enables selection against the receptor's extracellular region in its native conformation. Target cells may be either suspension or adherent. The primary objective is to identify peptides binding Tumor-Specific Receptors for targeted delivery of therapeutics or diagnostic agents.