Aggregation of Aβ42 and lysozyme in the presence & absence of the natural peptide Fasciculin-2 & the synthetic peptide KLVFF

Presence of insoluble proteinaceous deposits in human tissues is associated with the development of disorders such as amyloidosis and neurodegenerative diseases [1]. These proteinaceous deposits might generate through the effects of intracellular agents or induced environmental conditions which ultimately leads to covalent modification, consequent protein misfolding and its aggregation. Thus finding a way to inhibit these aggregates could have a great impact in prevention and therapy of the devastating diseases [2]. In this study, we examined, the effects of fasciculin II (Fas II) (a short, highly toxic peptide in the venom of Mamba snakes [3]), and a short synthetic peptide, named KLVFF, (derived from 16-20 residues of Aβ42 [4]), on the aggregation of lysozyme and Aβ42 through exertion of different experimental setups. The aggregates were detected by techniques such as fluorescence spectroscopy, atomic force microscopy, electrophoresis and rheology. Our results showed that Fas II reduced the aggregation potency of both lysozyme and Aβ, incubated for different lengths of incubation times. Despite KLVFF showed no significant effects on lysozyme aggregation, it could reduce Aβ42 aggregation considerably. Each of the above-mentioned experimental setups were also examined after proteolytic cleavage of lysozyme and Aβ by trypsin, which showed impressive effects on lysozyme and Aβ42 aggregates inhibition. These preliminary and promising results could be considered in the framework of using short length peptides as potential candidate drugs in the treatment of amyloidogenic diseases. Our rheological results demonstrated significant increment of incubated Lysozyme‟s viscosity compared with monomeric lysozyme and efficacy of rheology as a novel technique for aggregation assay.

Keywords:

Protein aggregation , Protein aggregation inhibition , Amyloid beta peptide , Lysozyme , Fasciculin II , KLVFF peptide