title: Morphology control between twisted ribbon, helical ribbon, and nanotube self-assemblies with his-containing helical peptides in response to pH change.
abstract: pH-Responsive molecular assemblies with a variation in morphology ranging from a twisted ribbon, a helical ribbon, to a nanotube were prepared from a novel A3B-type amphiphilic peptide having three hydrophilic poly(sarcosine) (A block) chains, a hydrophobic helical dodecapeptide (B block), and two histidine (His) residues between the A3 and B blocks. The A3B-type peptide adopted morphologies of the twisted ribbon at pH 3.0, the helical ribbon at pH 5.0, and the nanotube at pH 7.4, depending upon the protonation states of the two His residues. On the other hand, another A3B-type peptide having one His residue between the A3 and B blocks showed a morphology change only between the helical ribbon and the relatively planar sheets with pH variation in this range. The morphology change is thus induced by one- or two-charge generation at the linking site of the hydrophilic and hydrophobic blocks of the component amphiphiles but in different ways.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University , Kyoto-Daigaku-Katsura, Nishikyo-ku, 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; D046529:Microscopy, Electron, Transmission; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D055672:Static Electricity
chemical_list: D010455:Peptides; D006639:Histidine