X-ray Scattering Study of the Effect of Hydration on the Cross-;? Structure of Amyloid Fibrils

摘要

Amyloid fibrils formed from different peptides and proteins are associated with more than 20 diseases.Similar self-assembled structures form in vitro from a broad range of non-disease-related polypeptides.They are generally thought to adopt a common cross-beta structure in which the peptide chains assemble into beta-sheets,with-the constituent beta-strands running perpendicular to the fibril axis.The evidence for this structure comes from wide-angle X-ray scattering (WAXS) studies of aligned fibril samples that show the presence of characteristic anisotropic patterns consisting of an axial reflection at 4.7 A,corresponding to the inter-strand spacing,and an equatorial reflection at typically 8-12 A,which is usually broader and corresponds to the spacing between two or more beta-sheets stacked within the fibril.