Peptide Binding by One‐Armed Receptors in Water: Screening of a Combinatorial Library for the Binding of Val‐Val‐Ile‐Ala

A new class of one-armed cationic receptors has been found to bind the tetrapeptide Val-Val-Ile-Ala in water through a combination of electrostatic and hydrophobic interactions, to give a β-sheet-like structure as shown. Even within a small library of only 512 different members, the binding constants for the most efficient receptors of approximately 103–104 M−1 are more than a factor of 200 greater than those of the worst.