Ultra-large chemical libraries for the discovery of high-affinity peptide binders.

ABSTRACT: High-diversity genetically-encoded combinatorial libraries (10⁸-10¹³ members) are a rich source of peptide-based binding molecules, identified by affinity selection. Synthetic libraries can access broader chemical space, but typically examine only ~?10⁶ compounds by screening. Here we show that in-solution affinity selection can be interfaced with nano-liquid chromatography-tandem mass spectrometry peptide sequencing to identify binders from fully randomized synthetic libraries of 10⁸ members-a 100-fold gain in diversity over standard practice. To validate this approach, we show that binders to a monoclonal antibody are identified in proportion to library diversity, as diversity is increased from 10⁶-10⁸. These results are then applied to the discovery of p53-like binders to MDM2, and to a family of 3-19?nM-affinity, ?/?-peptide-based binders to 14-3-3. An X-ray structure of one of these binders in complex with 14-3-3? is determined, illustrating the role of ?-amino acids in facilitating a key binding contact.

SUBMITTER: Quartararo AJ 

PROVIDER: S-EPMC7311396 | biostudies-literature | 2020 Jun

REPOSITORIES: biostudies-literature