Translating antibody-binding peptides into peptoid ligands with improved affinity and stability

Area of Science:

• Biochemistry
• Chemical Biology
• Protein Engineering

Background:

• Protein-binding peptides are crucial in medicine and diagnostics.
• Peptide mimetics, like peptoids, offer enhanced stability and biorecognition.
• A strategy is needed to convert known peptides into effective peptoid analogues.

Purpose of the Study:

• To develop a method for translating protein-binding peptides into peptoid analogues.
• To create and evaluate peptoid analogues of the IgG-binding peptide HWRGWV.
• To assess the affinity, stability, and purification capabilities of these peptoid ligands.

Main Methods:

• Synthesized peptoid analogues by modifying the HWRGWV sequence.
• Screened variants using IgG binding tests and in silico docking simulations.
• Characterized selected peptoids (PL-16, PL-22) using binding isotherm analysis and purification assays.

Main Results:

• Selected peptoids showed strong binding to human IgG subclasses.
• Binding isotherm analysis revealed high capacity (Qmax ~48-57 mg/mL) and affinity (KD ~5.4-7.8 x 10^-7 M).
• Peptoid-based adsorbents achieved high IgG recovery (up to 85%) and purity (up to 98%) from cell culture supernatant.

Conclusions:

• The study presents a successful peptide-to-peptoid translation strategy.
• Developed peptoid ligands exhibit excellent stability and purification performance for IgG.
• This work provides a valuable method for designing peptoid variants of peptide ligands.