Figure Legends:
Figure 1. Location of di-D-amino acid substitutions.
Substitutions are indicated by bolded, underlined, italicized letters.
The substitutions were identical for Aβ40 and Aβ42, except for the
additional ia substitution in Aβ42.
Figure 2. Oligomerization of di-D-amino acid substituted
Aβ.
Peptides were cross-linked using PICUP. SDS-PAGE and silver staining
were then performed to observe the effects of substitutions on (a) Aβ40
and (b) Aβ42 (see text for explanation of colored arrows and peptide
designations). Mr indicates apparent molecular weight.
Lanes ”M” are molecular weight markers. Positions of D-amino acid
substitutions are indicated below each gel. Gels are representative of
three independent experiments.
Figure 3. Fibril formation kinetics of di-D-amino acid
substituted Aβ.
Peptides were prepared and mixed with Thioflavin T, which binds β-sheet
and can serve as a surrogate marker for aggregation. Error bars
represent standard deviations of three experiments. (A) Variants of Aβ40
with di-D-amino acid substitutions. (B) Variants of Aβ42 with di-D-amino
acid substitutions.
Figure 4. Location of single D-amino acid substitutions in Aβ40
and Aβ42.
Figure 5. Oligomerization of single D-amino acid
substituted Aβ.
Both non-cross-linked and cross-linked samples were analyzed. Peptide
samples were prepared and cross-linked using PICUP, and then analyzed
using SDS-PAGE and silver staining. (A) Non-cross-linked and
cross-linked Aβ40. Several substituted peptides behaved similar to WT,
(e.g., D-N27). Others only displayed monomer. (B) Oligomer distribution
frequencies of select Aβ40 variants. (C) Non-cross-linked and
cross-linked samples of Aβ42. (F) Oligomer distribution frequencies of
Aβ42. Gels are representative of three independent experiments.
Figure 6. Fibril formation kinetics of single