Aggregation of amyloid beta and lysozyme in the presence of fasciculin 2 and KLVFF

Abstract Protein deposits in the forms of fibrillar and/or amorphous structures can be detected in diseases such as systemic amyloidosis or neurodegenerative diseases. The formation of these aggregates might either be triggered by processes such as aging and/or environmental factors (e.g. life style) that ultimately, through protein folding/misfolding lead to aggregation. To find a way to delay of completely inhibit the formation of these aggregates, considering their great impact in human population, is of immediate concern. In this work, we examined the effects of fasciculin II (Fas II), a short, highly toxic peptide in the venom of Mamba snakes, and KLVFF, a short synthetic peptide, derived from 16-20 residues of Aβ42, on the aggregation of Aβ42 and lysozyme. The aggregates were detected by techniques such as fluorescence spectroscopy, atomic force microscopy, electrophoresis and rheology. Our results showed that Fas II lowered the aggregation potency of both lysozyme and Aβ. We also found that despite KLVFF showed no significant effects on lysozyme aggregation, it could reduce Aβ42 aggregation considerably. Each of the above-mentioned experiments were also performed after proteolytic cleavage of lysozyme and Aβ by trypsin that showed also showed decreases on lysozyme and Aβ42 aggregation. We also, examined rheological methodology to quantify the aggregates. We concluded that rheology could also be considered as a technique to be used in aggregation studies. This study provides another evidence for the using of short length peptides as candidate drugs in the treatment of amyloidogenic diseases.