view article

Figure 1
Data from the fibrillation process of GNNQQNY. (a) Normalized ThT fluorescence emission intensity recorded at the time that the samples were extracted from the fluorescence plate reader. Three fibrillation series are included: 8.7 and 8.6 mg ml−1 peptide in H2O (squares and circles) and 5.8 mg ml−1 peptide in 10% DMSO (triangles). Closed symbols correspond to the SAXS data used in the following analysis, while open symbols represent non-isotropic (and hence discarded) scattering data. Samples sonicated prior to SAXS data collection are shown by inverted triangles. Additionally, late measurements (stars; 10.7 and 13.1 h) from fibrillation of 6.1 mg ml−1 peptide in 10% DMSO were measured. SAXS data were obtained from samples pooled from two wells, and these data are only partially included in the following analysis (see §[link]3 for details). (b) SAXS data from the extracted samples [corresponding to filled symbols and stars in (a)]. Inset: enlargement of the data from 3.4 and 9.0 h showing increased intensity around s = 1.3 nm−1, while the data from the 10.7 and 13.1 h samples show a clear Bragg peak at s = 1.3 nm−1. (c) Eigenvalues from singular value decomposition (SVD), excluding the two late time points (10.7 and 13.1 h). Inset: the first ten eigenvectors from the SVD analysis. (d) Fibril volume fractions obtained from OLIGOMER analysis using the theoretical monomer and the 9.0 h samples as representatives of the two components. (e) Cross-sectional pair-distance distribution functions for the samples at 3.4, 9.0 and 10.7 h. (f) The colour scale from red to purple used in (b) and (e) to show the development over time. A superscript `a' indicates that the fibrillation conditions included 10% DMSO and a superscript `b' indicates that the sample was sonicated immediately before measuring the SAXS data.

Journal logoSTRUCTURAL
BIOLOGY
ISSN: 2059-7983
Follow Acta Cryst. D
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds