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：18
页码：7443-7448
DOI：10.1073/pnas.0812033106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Studies by solid-state nuclear magnetic resonance (NMR) of amyloid fibrils prepared in vitro from synthetic 40-residue {beta}-amyloid (A{beta}1-40) peptides have shown that the molecular structure of A{beta}1-40 fibrils is not uniquely determined by amino acid sequence. Instead, the fibril structure depends on the precise details of growth conditions. The molecular structures of {beta}-amyloid fibrils that develop in Alzheimer's disease (AD) are therefore uncertain. We demonstrate through thioflavin T fluorescence and electron microscopy that fibrils extracted from brain tissue of deceased AD patients can be used to seed the growth of synthetic A{beta}1-40 fibrils, allowing preparation of fibrils with isotopic labeling and in sufficient quantities for solid-state NMR and other measurements. Because amyloid structures propagate themselves in seeded growth, as shown in previous studies, the molecular structures of brain-seeded synthetic A{beta}1-40 fibrils most likely reflect structures that are present in AD brain. Solid-state 13C NMR spectra of fibril samples seeded with brain material from two AD patients were found to be nearly identical, indicating the same molecular structures. Spectra of an unseeded control sample indicate greater structural heterogeneity. 13C chemical shifts and other NMR data indicate that the predominant molecular structure in brain-seeded fibrils differs from the structures of purely synthetic A{beta}1-40 fibrils that have been characterized in detail previously. These results demonstrate a new approach to detailed structural characterization of amyloid fibrils that develop in human tissue, and to investigations of possible correlations between fibril structure and the degree of cognitive impairment and neurodegeneration in AD.
关键词：Alzheimer's disease ; electron microscopy ; solid-state nuclear magnetic resonance
