title: Molecular structure of glucopyranosylamide lipid and nanotube morphology.
abstract: A series of glucopyranosylamide lipids, N-(X-octadecenoyl)-beta-D-glucopyranosylamine [X = 13-cis (1), 11-cis (2), 9-cis (3), 6-cis (4), and 9-cis,12-cis (5)] and their saturated homologue N-octadecanoyl-beta-d-glucopyranosylamine (6), which differ in the position of a cis double bond in the C18 hydrocarbon chains, have been synthesized. The effect of the cis double bond position on the chiral self-assembly of each glycolipid has been examined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV, and circular dichroism (CD). The 11-cis derivative 2 was observed to self-assemble in water to form a uniform hollow cylinder structure with about 200-nm outer diameters in >98% yields. The obtained nanotubes from 2 showed the narrowest distribution of outer diameters and also gave a negative CD band around 234-236 nm, showing the largest CD intensity among the glycolipids investigated. Thus, we found that the position of a cis double bond significantly influences the homogeneity of the outer diameters as well as growth behavior of the self-assembled nanotube structures. Chiral molecular packing driven by a possible bending structure of the unsaturated glycolipids is playing a critical role in determining tubular morphology through molecular self-assembly.
authors.affiliation: CREST, Japan Science and Technology Corporation, Tsukuba Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Kamiya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Minamikawa
authors.forename: Jong Hwa
authors.initials: JH
authors.lastname: Jung
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Masuda
authors.forename: Toshimi
authors.initials: T
authors.lastname: Shimizu
mesh_terms: D000577:Amides / Q000737:chemistry*; D005944:Glucosamine / Q000031:analogs & derivatives* / Q000737:chemistry; D006017:Glycolipids / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D015394:Molecular Structure; D043942:Nanotubes / Q000737:chemistry*; D044367:Phase Transition; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000577:Amides; D006017:Glycolipids; D014867:Water; C075822:glucopyranosylamine; D005944:Glucosamine