Peptide Products

Modulation of Aβ aggregation and cytotoxicity by FLN. (A) CD spectra of Aβ monomer incubated for 7 days at 37°C in the absence (Aβ aggregate) or presence of 10x FLN (FLN). (B) TEM images of 50 μM of Aβ incubated for seven days at 37°C in the absence of any dye (Aβ only), or in the presence of 3x FLN. Scale bar is 100 nm. (C) Dot blot images of Aβ aggregates formed without (Aβ only) or with 3x and 10x FLN using OC and 4G8 antibodies. For each antibody, all samples were spotted onto one nitrocellulose membrane. Each membrane was immuno-stained with the OC or 4G8 antibody. For clearer presentation of the data, the sections of each membrane were cut and re-arranged. (D) Viability of neuroblastoma SH-SY5Y cells. Three controls (PBS buffer, Aβ monomer, and FLN) and two Aβ aggregates formed in the absence or presence of 3x FLN at 37°C for 5 days. Values represent means ± standard deviation (n≥3). Values are normalized to the viability of cells administered with PBS buffer only. Two-sided Student’s t-tests were applied to the MTT reduction data. (*; P = 0.013).

CD spectra of Aβ monomer and preformed Aβ aggregates. (A) CD spectra of Aβ monomer, Aβ aggregates formed in the absence or presence of 10x EOB or PHB for 5 days at 37°C. (B) CD spectra of Aβ aggregates formed in the absence or presence of 10x EOY, ERB, or ROB for 5 days at 37°C.

Directed folding of peptides containing four cysteine residues to bicyclic structures. a, The two CXC motifs in peptide 9 strongly promote the formation of a fused bicyclic structure. b, The CXC motif in 10 directs the intramolecular pairing of cysteine residues to two products and does not promote the formation of peptide dimers. c, The four isolated cysteine residues in 11 oxidize to form three products in statistically expected ratios. Oligomerization of 9–11 is never observed. Disulfide pairing was established by tryptic digestion LC-MS (Supplementary Figs S6–S10). aa, amino acid.