title: Negative thermal expansibility change for dissociation of lysozyme variant amyloid protofibril.
abstract: A disulfide-deficient variant of hen lysozyme, 0SS, is known to form an amyloid protofibril spontaneously, and to dissociate into monomers at high hydrostatic pressure. We carried out native PAGE at various temperatures (20-35°C) and pressures (0.1-200 MPa), to characterize the dissociation equilibrium of disulfide-deficient variant of hen lysozyme amyloid protofibril. Based on the density profiles, the partial molar volume and thermal expansibility changes for dissociation, ΔvD and ΔeD , were obtained to be -74 cm(3) /mol at 25°C and -2.3 cm(3) mol(-1) K(-1) , respectively. The dissociation of amyloid fibril destroys the cross β-structure, and such conformational destruction in native protein fold rarely accompanies negative thermal expansibility change. We discussed the negative thermal expansibility change in terms of hydration and structural packing of the amyloid protofibril.
authors: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu, Japan; RIKEN SPring-8 Center, Hyogo, Japan.
authors: Ryo
authors: R
authors: Ishiguro
authors: Hiroshi
authors: H
authors: Matsuo
authors: Keiichi
authors: K
authors: Kameyama
authors: Hideki
authors: H
authors: Tachibana
authors: Tetsuro
authors: T
authors: Fujisawa
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D002645:Chickens; D004591:Electrophoresis, Polyacrylamide Gel; D006358:Hot Temperature; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism*; D058767:Protein Unfolding; D013816:Thermodynamics
chemical_list: D000682:Amyloid; C421864:hen egg lysozyme; D009113:Muramidase
keywords: Dissociation equilibrium; High-pressure native polyacrylamide gel electro-phoresis; Partial molar volume; Thermal expansibility