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：34
页码：14339-14344
DOI：10.1073/pnas.0907821106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We demonstrate that accurate values of mass-per-length (MPL), which serve as strong constraints on molecular structure, can be determined for amyloid fibrils by quantification of intensities in dark-field electron microscope images obtained in the tilted-beam mode of a transmission electron microscope. MPL values for fibrils formed by residues 218-289 of the HET-s fungal prion protein, for 2-fold- and 3-fold-symmetric fibrils formed by the 40-residue {beta}-amyloid peptide, and for fibrils formed by the yeast prion protein Sup35NM are in good agreement with previous results from scanning transmission electron microscopy. Results for fibrils formed by the yeast prion protein Rnq1, for which the MPL value has not been previously reported, support an in-register parallel {beta}-sheet structure, with one Rnq1 molecule per 0.47-nm {beta}-sheet repeat spacing. Since tilted-beam dark-field images can be obtained on many transmission electron microscopes, this work should facilitate MPL determination by a large number of research groups engaged in studies of amyloid fibrils and similar supramolecular assemblies.
