Peptide‐Guided Assembly of Repeat Protein Fragments

• Published in: Angewandte Chemie International Edition Vol. 57; no. 17; pp. 4576 - 4579
• Main Authors: Michel, Erich, Plückthun, Andreas, Zerbe, Oliver
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 16.04.2018
• Edition: International ed. in English
• Subjects: Affinity; Amino acids; armadillo repeat; Assembly; Binders; Fragmentation; Fragments; peptide binding; Peptides; protein design; Proteins; repeat proteins; split proteins; split proteins; repeat proteins; protein design; peptide binding; armadillo repeat
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201713377

Herein, we present the peptide‐guided assembly of complementary fragments of designed armadillo repeat proteins (dArmRPs) to create proteins that bind peptides not only with high affinity but also with good selectivity. We recently demonstrated that complementary N‐ and C‐terminal fragments of dArmRPs form high‐affinity complexes that resemble the structure of the full‐length protein, and that these complexes bind their target peptides. We now demonstrate that dArmRPs can be split such that the fragments assemble only in the presence of a templating peptide, and that fragment mixtures enrich the combination with the highest affinity for this peptide. The enriched fragment combination discriminates single amino acid variations in the target peptide with high specificity. Our results suggest novel opportunities for the generation of new peptide binders by selection from dArmRP fragment mixtures. Optimizing the selectivity of proteins that already bind with very good affinities to peptides is difficult to achieve because the selection pressure is comparably low. A new method based on the use of complementary fragments of armadillo repeat proteins is proposed. The high discriminatory power of the system was confirmed by NMR analysis.