Peptides are short chains of amino acid residues linked by peptide bonds. Typically, they are produced by fragmentation of large proteins, recombinant expression, or chemically by solid-phase synthesis.
Conventional peptides have sometimes found limited therapeutic application, but interest in these molecules has been increasing due to their unique properties and ease of synthesis and manipulation. In the race to develop solutions for the COVID-19 pandemic, peptides are deemed crucial when:
- Developing epitope-specific antibodies (also called peptide antibodies) – peptides can help us direct the immune response towards a specific epitope linked with an essential function, such as ACE2 receptor binding within the S1 subunit in SARS-CoV-2.
- Performing exhaustive antibody characterization – peptides are crucial to characterize the specificity and assess the risk of cross-reactivity in newly generated antibodies. In these cases, peptides help us ensure the quality of the antibody even before it enrolls in preclinical and clinical trials.
- Vaccine design – peptides make attractive antigens, not only for their ability to generate a targeted immune response but also for their ability to build complex vaccine constructs to help us enhance that response. This can be achieved by using cell-penetrating peptides to ensure antigen delivery or using self-assembled peptides to build constructs that mimic the surface of the new coronavirus strain.
- Therapeutic peptide development – within the spike protein of SARS-CoV-2 there are specific regions that serve as attractive targets for therapeutic peptides. For instance, the S2 subunit is composed by heptad repeat 1 and 2 or HR1 and HR2. These regions assemble during the membrane fusion process forming the fusion core. By designing inhibitor peptides for this region, it may be possible to destabilize the fusion core and prevent the infect with SARS-CoV-2.
Peptides have multiple uses in the development of solutions to mitigate the effects of the COVID-19 pandemic. Moreover, their ease of synthesis and manipulation provides important advantages over integral proteins in therapy, research, and vaccination. For this reason, at ProteoGenix we will continue to ensure the production of high-quality peptides for diverse COVID-19-related strategies.