title: An alpha/beta-peptide helix bundle with a pure beta3-amino acid core and a distinctive quaternary structure.
abstract: Helix bundles are among the most widely studied tertiary and quaternary structural motifs in proteins. Here we present the crystal structure of an alpha/beta-peptide foldamer that adopts a tetrameric helix-bundle quaternary structure with a hydrophobic core composed solely of beta-amino acids. The structure displays features that are unprecedented among all known helix bundles composed of either alpha-peptides or peptidic foldamers. The tetramer is characterized by an asymmetry of interaction between neighboring helices, and the side-chain packing within the hydrophobic core differs fundamentally from the knobs-into-holes arrangement typical of most helix bundles.
authors: Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706, USA.
authors: Michael W
authors: MW
authors: Giuliano
authors: W Seth
authors: WS
authors: Horne
authors: Samuel H
authors: SH
authors: Gellman
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017433:Protein Structure, Secondary
chemical_list: D000596:Amino Acids; D010455:Peptides