title: Crystallographic characterization of tryptophan-containing peptide 3(10)-helices.
abstract: The molecular and crystal structures of four peptides containing one L-Trp guest residue in Aib (alpha-aminoisobutyric acid or C alpha-methyl alanine) host oligopeptide chains have been determined by X-ray diffraction. The peptides are Z-Aib-L-Trp-Aib-OMe, Z-(Aib)2-L-Trp-Aib-OMe, Z-(Aib)3-L-Trp-Aib-OtBu and Boc-(Aib)3-L-Trp-Aib-OMe. Right-handed beta-turns and incipient and fully developed 3(10)-helices are formed in the crystal state by the tri-, tetra- and pentapeptides, respectively. The Trp residue is easily accommodated in these folded structures. The average geometry and preferred conformation for the Trp indolyl side chain are also discussed.
authors.affiliation: Naval Research Laboratory, Washington, DC, USA.
authors.forename: C
authors.initials: C
authors.lastname: George
authors.forename: J L
authors.initials: JL
authors.lastname: Flippen-Anderson
authors.forename: A
authors.initials: A
authors.lastname: Bianco
authors.forename: M
authors.initials: M
authors.lastname: Crisma
authors.forename: F
authors.initials: F
authors.lastname: Formaggio
authors.forename: C
authors.initials: C
authors.lastname: Toniolo
mesh_terms: D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D014364:Tryptophan / Q000737:chemistry*
chemical_list: D009842:Oligopeptides; D014364:Tryptophan