Parameters influencing scaffold conformation.

<p>A) CD spectra and B) ThT fluorescence of tetrapalmitoylated peptides with shortened length, 9 or 5 amino acids (Palm1–9 in blue and Palm1–5 in orange respectively) or different order of amino acids, reverse or scrambled (Palm15-1 in green and scPalm15 in red, respectively) to model sequence Palm1–15. C) CD and D) ThT of tetrapalmitoylated peptides with different isoelectric point with pI (and net charge) value indicated on top of each column (Palm1–15(D7K) in green, Palm1–15(E3A, D7K) in blue, Palm1–15(E3K, D7K) in orange, Palm1–15(E3K, D7K, E11K) in red and Palm1–15 in black). E) CD and F) ThT of peptides with different number/position of palmitic chains (Palm1–15(1C) in orange, Palm1–15(2C) in red, Palm1–15(1N1C) in green, Palm1–15(4C) in blue and Palm1–15 in black). G) CD and H) ThT of peptides acylated with different lipid chain length (Acetyl1–15 in orange, Butyl1–15 in blue, Octyl1–15 in green, Dodecyl1–15 in red and Palm1–15 in black). Peptides were 30 µM in 2% HFIP/PBS (v/v) (CD) and 15 µM in 1% HFIP/PBS (v/v) (ThT, 24 µM). Fluorescence was measured at 485 nm with excitation at 440 nm. Values are the average of 3 replicates, normalized to the Palm1–15 emission (taken as 100%).</p

Peptide sequences of lipopeptides and controls.

<p>Peptide sequences of lipopeptides and controls.</p

Characterization of β-sheet amyloid-like aggregates of Palm1–15.

<p>A) CD spectra at 30 µM peptide Palm1–15 (green) and controls Acetyl1–15 (red) and Aβ1–15 (orange) in 2% HFIP/PBS (v/v). B) Profile of ThT emission with different peptide concentrations in the presence of 24 µM of dye. Fluorescence was measured at 485 nm with excitation at 440 nm. C, D, E) ssNMR of Palm1–15 uniformly labeled at Ala2, Ser8 and Gly9: (¹³C-¹³C) 2D PDSD correlation spectra with mixing times of 20 ms (C) and 150 ms (D); ¹H-¹³C FSLG-HETCOR spectra (E) together with chemical shift predictions based on secondary structure <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105641#pone.0105641-Wang1" target="_blank">[38]</a> (red for random coil, green for β-sheet, blue for α-helix). F) Electron micrographs of negatively stained Palm1–15 aggregates formed over 24 hour incubation in 2% HFIP/PBS (v/v). Samples were negatively stained with 2% Uranyl Acetate in water. Scale bar 0.1 µm. Magnification 22000 x.</p

ELISA.

<p>Optical density (OD) at 450 nm measured at 2.5 h of pNPP incubation. OD for the different compounds at different concentrations is given. A and B illustrate the ability of the compounds to recognize Aβ fibrils. They indicate two series of experiments performed with following compounds A: ACI-80-Kφ to ACI-86-Kφ. ACI-80 without φ-label was run as a control. B: ACI-87-Kφ to ACI-89-Kφ, as well as fluorinated derivatives. ACI-80-Kφ, ACI-82-Kφ and ACI-83-Kφ were included as controls. C and D illustrate the ability of the compounds to recognize peptide film which largely consists of Aβ monomers.</p

Pyroglutamate content of ACI-80, ACI-80-Kφ and [¹²⁷I]-ACI-80.

<p>Kφ presents a lysine (K) linked to a fluorescein isothiocyanate (φ).</p

D-enantiomeric peptide variants binding to fibrillar Aß1–42, covalently immobilized on a CM5 sensor chip via amine coupling.

<p>For each peptide variant experimental sensorgrams (black traces) obtained with injections at 2500 nM, 12500 nM and 62500 nM (ACI-80-Kφ, ACI-87-Kφ) or 500 nM, 2500 nM and 12500 nM (ACI-88-Kφ, ACI-89-Kφ) are shown. Injections were performed for 60 seconds each and dissociation phases were recorded for at least 30 seconds. The sensorgrams were globally fit (red curves) to a heterogeneous ligand model accounting for different refractive indices.</p

List of investigated D-enantiomeric peptide compounds.

<p>Modifications in the original amino acid sequence of ACI-80 are printed in bold. Amino acid residues are given in the one-letter-code. All amino-acids are D-enantiomers. Kφ presents a lysine (K) linked to a fluorescein isothiocyanate (φ).</p

Results for compound – Aβ fibril interactions obtained with the heterogeneous ligand model.

<p>Results for compound – Aβ fibril interactions obtained with the heterogeneous ligand model.</p

ELISA: Mean binding values for compounds with concentration of 10 µg/ml.

<p>All values were compared to that of ACI-80-Kφ. Compound binding to compound film, containing predominantly monomers and to fibrils was measured. Average values of two or three experiments unless marked otherwise. *value of one single experiment only. Kφ presents a lysine (K) linked to a fluorescein isothiocyanate (φ).</p

Photomicroscope images of mouse brain sections (female APP (V717I) × PS1 (A246E), age 24.3 months) in light microscope.

<p>Overview (left panel) and higher magnification (right panel). The brain slices were incubated with ACI-89-Kφ-peptide binding to plaques was visualized using an anti-fluorecein isothiocyanate 1 antibody and alkaline phosphatase as chromogenic detection. This revealed the high sensitivity of this method and the presence of abundant plaques in the tg mouse brain.</p