Tethered yeast surface display system enables efficient epitope-specific binder screening and enrichment

Engineering therapeutic proteins often faces a major hurdle: efficiently screening for binding to specific epitopes to achieve a desired function. Current strategies are often low-throughput and lack the precision needed to rapidly identify binders that target critical sites, leading to extensive downstream epitope mapping. This gap significantly slows down the development of novel protein therapeutics, particularly those requiring precise protein-protein interaction modulation or receptor antagonism at specific binding sites.

Researchers designed a novel tethered yeast surface display construct to facilitate epitope-specific binding interactions. This system leverages high local concentrations by tethering a candidate protein binder to a target protein of interest (POI) via a flexible peptide linker. The core of the assay involves screening for epitope-specific binders based on a decreased fluorescent signal due to inhibitory function when the construct is assayed alongside a competitive POI binder. They demonstrated the feasibility of this epitope-specific screening and enrichment, and systematically studied key optimization parameters to refine the method's performance.

The developed tethered yeast surface display system successfully demonstrated the capability for epitope-specific screening and enrichment of protein binders. By creating high local concentrations through a flexible peptide linker, the system effectively enabled the identification of binders that specifically target a desired epitope. This was achieved by observing a decreased fluorescent signal when an inhibitory binder was present, indicating successful competition at the target epitope. Key optimization parameters were identified and studied, confirming the robustness and tunability of the platform. The system's ability to screen based on inhibitory function directly addresses the challenge of identifying functionally relevant binders early in development.

Epitope-specific screening and enrichment was demonstrably possible based on fluorescent output, significantly streamlining the identification of functional protein binders.