Design and biological activity of β-sheet breaker peptide conjugates

The sequence LPFFD (iAβ5) prevents amyloid-β peptide (Aβ) fibrillogenesis and neurotoxicity, hallmarks of Alzheimer’s disease (AD), as previously demonstrated. In this study iAβ5 was covalently linked to poly(ethylene glycol) (PEG) and the activity of conjugates was assessed and compared to the activity of the peptide alone by in vitro studies. The conjugates were characterized by MALDI-TOF. Competition binding assays established that conjugates retained the ability to bind Aβ with similar strength as iAβ5. Transmission electron microscopy analysis showed that iAβ5 conjugates inhibited amyloid fibril formation, which is in agreement with binding properties observed for the conjugates towards Aβ. The conjugates were also able to prevent amyloid-induced cell death, as evaluated by activation of caspase 3. These results demonstrated that the biological activity of iAβ5 is not affected by the pegylation process.