Formation of amyloid fibrils from fully reduced hen egg white lysozyme.
The fully reduced hen egg white lysozyme (HEWL), which is a good model of random coil structure, has been converted to highly organized amyloid fibrils at low pH by adding ethanol. In the presence of 90% (v/v) ethanol, the fully reduced HEWL adopts beta-sheet secondary structure at pH 4.5 and 5.0, and an alpha-to-beta transition is observed at pH 4.0. A red shift of the Congo red absorption spectrum caused by the precipitation of the fully reduced HEWL in the presence of 90% (v/v) ethanol is typical of the presence of amyloid aggregation. EM reveals unbranched fibrils with a diameter of 2-5 nm and as long as 1-2 microm. The pH dependence of the initial structure of the fully reduced HEWL in the presence of 90% (v/v) ethanol suggests that Asp and His residues may play an important role.
Cao
Aoneng
A
College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, People's Republic of China.
Hu
Daoying
D
Lai
Luhua
L
D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D002645:Chickens; D002942:Circular Dichroism; D004529:Egg White; D005260:Female; D008854:Microscopy, Electron; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D020836:Protein Structure, Quaternary
D000682:Amyloid; D009113:Muramidase