title: Conformation of poly(γ-glutamic acid) in aqueous solution.
abstract: Local conformation and overall conformation of poly(γ-DL-glutamic acid) (PγDLGA) and poly(γ-L-glutamic acid) (PγLGA) in aqueous solution was studied as a function of degree of ionization ε by (1) H-NMR, circular dichroism, and potentiometric titration. It was clarified that their local conformation is represented by random coil over an entire ε range and their overall conformation is represented by expanded random-coil in a range of ε > ε(*) , where ε(*) is about 0.3, 0.35, 0.45, and 0.5 for added-salt concentration of 0.02M, 0.05M, 0.1M, and 0.2M, respectively. In a range of ε < ε(*) , however, ε dependence of their overall conformation is significantly differentiated from each other. PγDLGA tends to aggregate intramolecularly and/or intermolecularly with decreasing ε, but PγLGA still behaves as expanded random-coil. It is speculated that spatial arrangement of adjacent carboxyl groups along the backbone chain essentially affects the overall conformation of PγGA in acidic media.
authors.affiliation: Research Institute of Science and Technology, Nihon University, 1-8-1 Kanda-Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Muroga
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Nakaya
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Atsuki
authors.initials: A
authors.lastname: Inoue
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Itoh
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Abiru
authors.affiliation: Research Institute of Science and Technology, Nihon University, 1-8-1 Kanda-Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Kaori
authors.initials: K
authors.lastname: Wada
authors.affiliation: Nihon University Junior College, 7-24-1 Narashinodai, Funabashi, 274-8501, Japan.
authors.forename: Masako
authors.initials: M
authors.lastname: Takada
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.|Center for Creative Materials Research, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ikake
authors.affiliation: College of Science and Technology, Nihon University, 1-8-14 Kanda -Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.|Center for Creative Materials Research, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-Ku, Tokyo, 101-8308, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shimizu
mesh_terms: D002942:Circular Dichroism; D008968:Molecular Conformation; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D066244:Proton Magnetic Resonance Spectroscopy; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; C511775:poly(gamma-glutamic acid); D014867:Water; D011099:Polyglutamic Acid
keywords: conformational transition; helical chain; poly(α-glutamic acid); poly(γ-glutamic acid); potentiometric titration; random coil