ジャーナル: Proc Natl Acad Sci U S A / 年: 2009 タイトル: Comparison of Alzheimer Abeta(1-40) and Abeta(1-42) amyloid fibrils reveals similar protofilament structures. 著者: Matthias Schmidt / Carsten Sachse / Walter Richter / Chen Xu / Marcus Fändrich / Nikolaus Grigorieff / 要旨: We performed mass-per-length (MPL) measurements and electron cryomicroscopy (cryo-EM) with 3D reconstruction on an Abeta(1-42) amyloid fibril morphology formed under physiological pH conditions. The ...We performed mass-per-length (MPL) measurements and electron cryomicroscopy (cryo-EM) with 3D reconstruction on an Abeta(1-42) amyloid fibril morphology formed under physiological pH conditions. The data show that the examined Abeta(1-42) fibril morphology has only one protofilament, although two protofilaments were observed with a previously studied Abeta(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 Abeta(1-42) and Abeta(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 Abeta(1-40) and Abeta(1-42) fibrils have the same number of Abeta molecules per cross-beta repeat. Based on this data and the previously studied Abeta(1-40) fibril structure, we describe a model for the arrangement of peptides within the Abeta(1-42) fibril.