title: Self-assemblies of triskelion A2B-type amphiphilic polypeptide showing pH-responsive morphology transformation.
abstract: A pH-responsive rolled-sheet morphology was prepared from a triskelion A(2)B-type amphiphilic polypeptide having a histidine residue as a pH-responsive unit. The dimensions of the rolled sheet were 85 nm diameter and 210 nm length with a sheet turn number of 2.0 at pH 7.4. Upon decreasing the pH from 7.4 to 5.0, the layer spacing of the rolled sheets was widened from ca. 9 to ca. 19 nm due to electrostatic repulsion caused by histidine protonation. This morphology change occurred reversibly with a pH change between 7.4 and 5.0. The molecular packing in the rolled sheets was shown to be loosened at pH 5.0 on the basis of electron diffraction measurements. The tightness of the rolled sheets was thus controlled reversibly by a pH change due to a single protonation in the amphiphilic polypeptide.
authors.affiliation: Department of Material of Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-Daigaku-Katsura, Kyoto 615-8510, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Uesaka
authors.forename: Motoki
authors.initials: M
authors.lastname: Ueda
authors.forename: Akira
authors.initials: A
authors.lastname: Makino
authors.forename: Tomoya
authors.initials: T
authors.lastname: Imai
authors.forename: Junji
authors.initials: J
authors.lastname: Sugiyama
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Kimura
mesh_terms: D006639:Histidine / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D009584:Nitrogen / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary
chemical_list: D010455:Peptides; D006639:Histidine; D009584:Nitrogen