Figure 3.

(A) Prediction-based synthetic peptide library composed of thirty-one hexapeptide and one decapeptide designed for testing the predictions of fibrillogenic/aggregation prone sequences in the rV_L protein 6aJL2²⁹ generated by the web-based computational tools ZipperDB²⁶ and AmylPred2²⁸. The arrows point the consensus sequences predicted to be aggregation/fibrillogenic-prone by the tool AmylPred2. The sequences underlined and italized represent the hexapeptides forming steric zippers with a fit energy of −23 kcal/mol or lower, as calculated with RosettaDesign⁷¹. Segments with energies equal to or below this threshold are deemed to have high fibrillation propensity²⁷. (B) Aggregation assay of the synthetic peptides composing the prediction-based peptide library. The data represented is the thioflavin T (ThT) fluorescence intensity of the peptide samples (250 µM peptide dilution in PBS pH 7.4 plus 0.05% Na Azide), measured after 24 hours of incubation at 37 °C with constant agitation. Two replicas of the experiment were performed with very similar results (Result not shown). (C–H) Transmission electron micrographs of the aggregates present in the end-point samples of the synthetic peptides Ile30-Gln37 (C,D), Ile30-Val33 (E), and Ser30b-Trp35 (F–H).