Peptide beta-Bend and 3(10)-Helix: from 3D-Structural Studies to Applications as Templates.

The 3(10)-helix is a relatively common secondary structure motif in peptides and proteins. Its building block is one of various types of beta-bend conformation which comprises an N(alpha)-acylated dipeptide alkylamide system. A complete 3D-structural characterization of this ternary helix has been achieved, thus allowing its unambiguous discrimination from the closely related a-helix. Recent applications of rigidified peptide beta-bends and 3(10)-helices as templates for investigations in synthetic organic chemistry (macrocyclization, catalysis), host-guest chemistry (molecular recognition), and physical chemistry (donor-acceptor interaction) will be discussed.