The Role of Lys Side Chains in the Stabilization of β-Turn Structure

Abstract

Peptides containing Lys and Orn were synthesized to study the role of side chains in the formation of the β-turn structure. In contrast with peptides having a –Lys–Asp– sequence, peptides containing an –Orn–Asp– sequence do not adopt a β-turn structure. Analysis of the side chain rotamers shows that in Boc–Gly–Lys–Asp–Gly–OMe the Lys side chain can interact with the side chain of the neighboring Asp residue and this interaction contributes to the stabilization of the β-turn structure. The Orn side chain, instead of side chain–side chain interactions, interacts with the peptide backbone.