title: Aggregates with lysozyme and ovalbumin show features of amyloid-like fibrils.
abstract: The interaction of egg-white lysozyme with N-ovalbumin, the native form of egg-white ovalbumin with the denaturation temperature, T(m), of 78 °C, was investigated by the inhibition of lysozyme muramidase activity, differential scanning calorimetry, and circular dichroism assay as indicators. Signals for the interaction were the most prominent when the mixture of lysozyme and N-ovalbumin was co-heated at 72 °C, slightly lower than the T(m) of N-ovalbumin. The interaction was also marked when unheated lysozyme was mixed with N-ovalbumin preheated at 72 °C. Moreover, the mixture rapidly formed fibrous precipitates, which were positive for thioflavin T fluorescent emission, a marker for the amyloid fibril formation. Also electron microscopic observation exhibited features of fibrils. The interaction potency of ovalbumin was ascribed to the tryptic fragment ILELPFASGT MSMLVLLPDE VSGLEQLESIINFEK (residues 229-263), derived from the 2B strands 2 and 3 of ovalbumin. From lysozyme, on the other hand, the chymotryptic peptide RNRCKGTDVQAW (residues 112-123), including cluster 6, and the chymotryptic/tryptic peptide GILQINSRW (residues 54-62), including cluster 3, were responsible for the interaction with N-ovalbumin. Interestingly, this nonamer peptide was found to have the ability to self-aggregate. To the authors knowledge, this may be the first report to document the possible involvement of dual proteins in the formation of amyloid-like fibrils.
authors: The United Graduate School of Agricultural Sciences, Kagoshima University, Kagoshima 890-0065 Japan. yasushi@chem.agri.kagoshima-u.ac.jp
authors: Yasushi
authors: Y
authors: Sugimoto
authors: Yoshiki
authors: Y
authors: Kamada
authors: Yuhei
authors: Y
authors: Tokunaga
authors: Hiroshi
authors: H
authors: Shinohara
authors: Mitsuharu
authors: M
authors: Matsumoto
authors: Takahiro
authors: T
authors: Kusakabe
authors: Takatoshi
authors: T
authors: Ohkuri
authors: Tadashi
authors: T
authors: Ueda
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry* / Q000648:ultrastructure; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D004791:Enzyme Inhibitors / Q000737:chemistry; D005453:Fluorescence; D006358:Hot Temperature; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry*; D010047:Ovalbumin / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D011489:Protein Denaturation; D025941:Protein Interaction Mapping; D059748:Proteolysis; D013997:Time Factors
chemical_list: D000682:Amyloid; D004791:Enzyme Inhibitors; D010455:Peptides; D010047:Ovalbumin; D009113:Muramidase