title: Ordering in aqueous polysaccharide solutions. I. Dielectric relaxation in aqueous solutions of a triple-helical polysaccharide schizophyllan.
abstract: Deuterium oxide solutions of a triple-helical polysaccharide schizophyllan, undergoing an order-disorder transition centered around 17 degrees C, were studied by the time-domain reflectometry (TDR) to obtain dielectric dispersions in the solution and frozen states. In the solution state, the dispersion below the transition temperature is resolved in three dispersions (relaxation times at 0 degrees C) ascribed to side chain glucose residue (1; 102 ns), structured water (s; 2.0 ns) and bulk water (h), respectively, from low to high frequencies. Bulk water is divided into slow water (h2; 0.04 ns) and free or pure water (h1; 0.02 ns). Above the transition temperature structured water almost disappears and is compensated by slow water. Structured water is similar to bound water for proteins but different from it because of this transition behavior. Another dispersion (l) seen at the lowest frequency is assigned to the rotation of side-chain glucose residue coupled with hydrated water. Parts of this dispersion and structured water are suggested to constitute bound water. In the frozen state were observed a major dispersion (h; 0.14 ns) and a minor one (m; 28 ns), which were ascribed to considerably mobile and less mobile waters. They are similar to but not exactly the same as that for unfreezable water in bovine serum albumin solutions argued by Miura et al. (Biopolymers, 1995, Vol. 36, p. 9). Water is molded into different structures by the triple helix.
authors.affiliation: Department of Physics, Faculty of Science, Tokai University, Hiratsuka-shi, Kanagawa 259-12, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Naoki
authors.initials: N
authors.lastname: Shinyashiki
authors.forename: Shin
authors.initials: S
authors.lastname: Yagihara
authors.forename: Kazuto
authors.initials: K
authors.lastname: Yoshiba
authors.forename: Akio
authors.initials: A
authors.lastname: Teramoto
authors.forename: Naotake
authors.initials: N
authors.lastname: Nakamura
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Michio
authors.initials: M
authors.lastname: Sorai
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
mesh_terms: D001704:Biopolymers / Q000737:chemistry; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004563:Electrochemistry; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry; D012566:Sizofiran / Q000737:chemistry*; D012996:Solutions; D013696:Temperature; D014867:Water
chemical_list: D001704:Biopolymers; D011506:Proteins; D012996:Solutions; D014867:Water; D012566:Sizofiran