The interaction between Alzheimer amyloid beta(1-40) peptide and ganglioside GM1-containing membranes.

The interaction between Alzheimer amyloid peptide A beta(1-40) and membrane lipids was studied by circular dichroism spectroscopy under the conditions of physiologically relevant ionic strength and neutral pH. The peptide binds to the membranes containing ganglioside GM1 and upon binding undergoes a conformational transition from random coil to an ordered structure rich in beta-sheet. This interaction appears to be ganglioside-specific as no changes in A beta(1-40) conformation were found in the presence of various phospholipids or sphingomyelin. The isolated oligosaccharide moiety of the ganglioside was ineffective in inducing alterations in the secondary structure of A beta(1-40). No interaction was observed between ganglioside GM1 and the N-terminal peptide fragment A beta(1-28). Binding to the ganglioside is likely to modulate the neurotoxic and/or amyloidogenic properties of A beta(1-40).