Amyloid-like formation by self-assembly of peptidolipids in two dimensions

The accumulation of β-amyloid peptide (Aβ) in the human brain is known to be the major cause that drives Alzheimer's disease pathogenesis. Aβ, a 39-42 amino acid peptide, is the cleavage product of amyloid precusor protein in the hydrophobic transmembrane region. The present study employs a two-dimensional (2D) approach. Two synthetic peptidolipids, C ₁₈-IIGLM-OH and C ₁₈-IIGLM-NH ₂, are selected based on the fragment 31-35 of Aβ which is recognized as one of the determining segments that induces formation of amyloid fibril plaques. The aliphatic hydrocarbon chain C ₁₈ is attached to the N-terminal of the fragment 31-35 to facilitate the 2D study at the air-water interface. The aggregation process is observed by two measurements: (1) surface pressure-area and surface dipole moment-area isotherms and (2) epifluorescence microscopy of the Langmuir films to investigate the topography of the amyloid-like formation.