期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：47
页码：19813-19818
DOI：10.1073/pnas.0905007106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We performed mass-per-length (MPL) measurements and electron cryomicroscopy (cryo-EM) with 3D reconstruction on an A{beta}(1-42) amyloid fibril morphology formed under physiological pH conditions. The data show that the examined A{beta}(1-42) fibril morphology has only one protofilament, although two protofilaments were observed with a previously studied A{beta}(1-40) fibril. The latter fibril was resolved at 8 A resolution showing pairs of {beta}-sheets at the cores of the two protofilaments making up a fibril. Detailed comparison of the A{beta}(1-42) and A{beta}(1-40) fibril structures reveals that they share an axial twofold symmetry and a similar protofilament structure. Furthermore, the MPL data indicate that the protofilaments of the examined A{beta}(1-40) and A{beta}(1-42) fibrils have the same number of A{beta} molecules per cross-{beta} repeat. Based on this data and the previously studied A{beta}(1-40) fibril structure, we describe a model for the arrangement of peptides within the A{beta}(1-42) fibril.
关键词：Alzheimer's disease ; electron microscopy ; prion ; protein folding
