title: Analysis of core region from egg white lysozyme forming amyloid fibrils.
abstract: Some of the lysozyme mutants in humans cause systemic amyloidosis. Hen egg white lysozyme (HEWL) has been well studied as a model protein of amyloid fibrils formation. We previously identified an amyloid core region consisting of nine amino acids (designated as the K peptide), which is present at 54-62 in HEWL. The K peptide, with tryptophan at its C- terminus, has the ability of self-aggregation. In the present work we focused on its structural properties in relation to the formation of fibrils. The K peptide alone formed definite fibrils having β-sheet structures by incubation of 7 days under acidic conditions at 37°C. A substantial number of fibrils were generated under this pH condition and incubation period. Deletion and substitution of tryptophan in the K peptide resulted in no formation of fibrils. Tryptophan 62 in lysozyme was suggested to be especially crucial to forming amyloid fibrils. We also show that amyloid fibrils formation of the K peptide requires not only tryptophan 62 but also a certain length containing hydrophobic amino acids. A core region is involved in the significant formation of amyloid fibrils of lysozyme.
authors: Laboratory of Biochemistry and Bioscience The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065 Japan.
authors: Yuhei
authors: Y
authors: Tokunaga
authors: Yukako
authors: Y
authors: Sakakibara
authors: Yoshiki
authors: Y
authors: Kamada
authors: Kei-ichi
authors: K
authors: Watanabe
authors: Yasushi
authors: Y
authors: Sugimoto
mesh_terms: D000596:Amino Acids / Q000235:genetics; D000682:Amyloid / Q000235:genetics*; D000818:Animals; D001703:Biophysics; D002645:Chickens; D005453:Fluorescence; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D009113:Muramidase / Q000235:genetics*; D009842:Oligopeptides / Q000235:genetics*; D017433:Protein Structure, Secondary; D013696:Temperature
chemical_list: D000596:Amino Acids; D000682:Amyloid; D009842:Oligopeptides; C421864:hen egg lysozyme; D009113:Muramidase
keywords: amyloid fibril formation; core region; egg white.; lysozyme; tryptophan