Membrane Determinants Affecting Fibrillation Processes of β-Sheet Charged Peptides

β-sheet is one of the elementary secondary structures of proteins that is of wide interest from a motif applied to new and designed biomaterials for medical implications related to the fact that this motif appears in misfolded proteins, amyloids, in neurodegenerative diseases. Aside to the huge potential of using peptides for various biological, biotechnological and medical applications, there is a growing interest in understanding their interaction mechanism with biological tissues.

Here we investigated a group of amphiphilic and charged β-sheet model peptides, capable of forming fibril and hydrogels that may exert different biological effects. In biological milieu, the effect of the charged peptides could be highly mediated by interactions with mammals` cell membranes and or bacteria. To unravel the possible mechanisms of peptides in such systems, it is important to study and characterize the various modulating effects lipids may have on such peptides and vice versa.

The model peptides used, differ in their charged residues only, were studied for their charge dependent membrane interactions. Charged lipid vesicles, mimicking membrane bilayer, were found to affect especially zwitterion peptide tendency to form β-structure and induced unique fibril morphology. These interactions were found to be asymmetric and did not change the vesicle surface fluidity. However, electrostatic interactions occurred between the cationic peptide and the negatively charged vesicle, changing its surface rigidity and fluidity. The results may indicate the occurrence of charged dependent interaction between charged membranes and peptides.