title: Amyloid fibril formation from a 9 amino acid peptide, 55th-63rd residues of human lysozyme.
abstract: Hen egg white lysozyme (HEWL) readily forms amyloid fibrils in vitro. We have previously identified a core structure, termed HEWL K-peptide, involved in fibril formation. Two major peptides, peptide #3 (50th-102nd residues of human lysozyme (hLZ)) and peptide #5 (54th-102nd residues), were isolated from the hLZ amyloid fibrils that had been exposed to pH 2.0 and 58 °C, and precipitated by ultra-centrifugation. These peptides cover most of the beta-domain and C-helix of hLZ including a 9 residues sequence corresponds to a human counterpart of HEWL K-peptide, GIFQINSRY (55th-63rd residues of hLZ, thus named "human K-peptide"). Chemically synthesized human K-peptide readily formed amyloid fibrils, as in HEWL K-peptide. It was demonstrated that both at least 9 residue length and Phe residue at 3rd position of the human K-peptide were crucial for amyloidogenesis in vitro. Short peptides covering COOH-terminal region of peptides #3 and #5 did not form amyloid fibrils. These data suggested that human K-peptide region with high propensity of amyloidogenesis plays a key role as a fibril-forming core sequence of hLZ. Interestingly, human K-peptide region is flanked by two predicted semi-disordered regions (39th-52nd and 67th-75th residues). We discuss the possible role of these regions.
authors.affiliation: The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-0065, Japan. Electronic address: k0085039@kadai.jp.
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Tokunaga
authors.affiliation: Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-0065, Japan.
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Matsumoto
authors.affiliation: The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24, Korimoto, Kagoshima 890-0065, Japan. Electronic address: yasushi@chem.agri.kagoshima-u.ac.jp.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sugimoto
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D013696:Temperature
chemical_list: D000682:Amyloid; D010446:Peptide Fragments; D009113:Muramidase
keywords: Acid hydrolysis; Amyloid fibril; Core peptide; Hen egg white lysozyme; Human lysozyme; β-Structure