title: Effects of D-Leu residues on the helical secondary structures of L-Leu-based nonapeptides.
abstract: The influence of D-Leu residues on the helical structures of L-Leu-based-nonapeptides was investigated. Specifically, the preferred conformations of four diastereomeric nonapeptides, Boc-(L-Leu-L-Leu-Aib)3-OMe (1); Boc-(L-Leu-L-Leu-Aib)2-L-Leu-D-Leu-Aib-OMe (2), which contained one D-Leu residue; Boc-L-Leu-D-Leu-Aib-L-Leu-L-Leu-Aib-L-Leu-D-Leu-Aib-OMe (3), which contained two D-Leu residues; and Boc-(L-Leu-D-Leu-Aib)3-OMe (4), were analyzed in solution and in the crystalline state. Peptide 1 formed a right-handed (P) 310-helix in solution. Peptides 2 and 3 both formed (P) 310-helices in solution and (P) α-helices in the crystalline state. Peptide 4 formed a (P) α-helix both in solution and in the crystalline state.
authors.affiliation: Division of Organic Chemistry, National Institute of Health Sciences.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Demizu
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamashita
authors.forename: Takashi
authors.initials: T
authors.lastname: Misawa
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Doi
authors.forename: Masakazu
authors.initials: M
authors.lastname: Tanaka
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kurihara
mesh_terms: D007930:Leucine / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry*; D009904:Optical Rotation; D017433:Protein Structure, Secondary; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D009842:Oligopeptides; D007930:Leucine