Combinatorial deep mutational scanning uncovers protein superbinders and molecular determinants of epistasis.

Combinatorial deep mutational scanning reveals epistatic superbinders that bind 3- to 5-fold tighter than existing PIN1 WW-domain binders.

• Why it matters: Understanding non-linear amino-acid interactions is crucial for designing high-affinity protein binders, but traditional methods overlook these epistatic effects.
• What they did: Using the ORCHID approach, the study systematically maps epistasis across all mutational contexts with a peptide display assay involving 45% improved prediction accuracy over non-epistatic models.
• The result: Two superbinders, SPY-tide and LYR-tide, were identified and structurally characterized, revealing molecular determinants of epistasis that can inform improved binder design and natural peptide recognition.