title: Molecular assembly formation of cyclic hexa-beta-peptide composed of acetylated glycosamino acids.
abstract: A novel cyclic hexamer of acetylated beta-glycosamino acid was synthesized and its conformation and molecular assembly formation was investigated. Variable temperature NMR study indicated that the cyclic hexapeptide took a C(3) symmetric conformation at room temperature, but at elevated temperatures a C(6) symmetric one, which was not due to averaging of the C(3) symmetric conformation, appeared. Computational geometry optimization showed that the C(6) symmetric conformation was a highly planar structure with amide groups orienting perpendicular to the ring plane. The cyclic hexa-beta-peptide formed rod-shaped crystals from an N,N-dimethyl formamide solution at elevated temperature. The optical microscopy observation with a sensitive tint plate under cross-nicol configuration and electron diffraction analysis of the crystals revealed that the cyclic hexa-beta-peptides were stacked one after the other to form a regular nanotube structure.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Kyoto, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Hirata
authors.forename: Futoshi
authors.initials: F
authors.lastname: Fujimura
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Horikawa
authors.forename: Junji
authors.initials: J
authors.lastname: Sugiyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Morita
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Kimura
mesh_terms: D000107:Acetylation; D000596:Amino Acids / Q000138:chemical synthesis / Q000737:chemistry; D003460:Crystallization; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008958:Models, Molecular; D015394:Molecular Structure; D043942:Nanotubes; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry*; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D009842:Oligopeptides; D010456:Peptides, Cyclic