Circular Permutation of the Trp-cage: Fold Rescue upon Addition of a Hydrophobic Staple

RSC Adv. 2013 Nov 21;2013(43):10.1039/C3RA43674H. doi: 10.1039/C3RA43674H.

Abstract

The Trp-cage, at 20 residues in length, is generally acknowledged as the smallest fully protein-like folding motif. Linking the termini by a two-residue unit and excising one residue affords circularly permuted sequences that adopt the same structure. This represents the first successful circular permutation of any fold of less than 50-residue length. As was observed for the original topology, a hydrophobic staple near the chain termini is required for enhanced fold stability.