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Pallbo, J.*; Imai, Masayuki*; Gentile, L.*; Takata, Shinichi; Olsson, U.*; Sparr, E.*
Frontiers in Physiology (Internet), 11, p.592117_1 - 592117_13, 2020/12
Times Cited Count：6 Percentile：39.96(Physiology)Fujiwara, Satoru; Matsumoto, Fumiko*; Yonezawa, Yasushige*
Journal of Molecular Biology, 331(1), p.21 - 28, 2003/08
Times Cited Count：45 Percentile：59.07(Biochemistry & Molecular Biology)The kinetic process of the fibril formation of hen egg white lysozyme (HEWL) in 90% ethanol in various salt concentrations has been investigated with time-resolved neutron scattering. It was shown that by addition of NaCl in a range between 0.3 mM and 1.0 mM, gelation occurred, and this gelation proceed through a two-step process; the lateral association of the protofilaments formed by HEWL, followed by the cross-linking of these fibrils formed. Both the structures of the fibrils and the rate of the gelation depended on NaCl concentration. Above 2 mM NaCl, precipitation occurred because of the formation of amorphous aggregates. Sensitivity of the aggregated structures to salt concentration suggests that electrostatic interaction plays an essential role in the formation of these structures. The structural diversity both in the fibrils and the aggregated structures of the fibrils can be interpreted in terms of the difference in the degree of the electrostatic shielding at different salt concentrations.
Yonezawa, Yasushige*; Tanaka, Shimpei*; Kubota, Tomomi*; Wakabayashi, Katsuzo*; Yutani, Katsuhide*; Fujiwara, Satoru
Journal of Molecular Biology, 323(2), p.237 - 251, 2002/10
Times Cited Count：76 Percentile：75.11(Biochemistry & Molecular Biology)It is known that hen egg white lysozyme (HEWL) forms amyloid fibrils in highly concentrated ethanol solutions. In order to gain an insight into the mechanism of the amyloid fibril formation, the structures of HEWL in solutions of various protein and ethanol concentrations were investigated with small-angle X-ray and neutron scattering. It was shown that the structural states of HEWL were distinguished as the monomer state, the state of the dimer formation, the state of the protofilament formation, the protofilament state, and the state towards the formation of the amyloid fibrils. Circular dichroism measurements showed that the large changes in the secondary structures of HEWL occurred during the dimer formation. Structural characterization showed that the dimers had an elongated shape, the protofilaments were formed by stacking of the dimers with their long axis (nearly) perpendicular to the protofilament axis, and the changes of the structural states towards the amyloid fibril formation occurred via lateral association of the protofilaments.
