Filamentous Supramolecular Structures

Summary: The formation of four filament forming proteins was studied mainly by light scattering as a function of the scattering angle. Besides the molar mass M_w and the radius of gyration R_g the contour length L, was determined. The corresponding structure parameters are compared with those of the Aβ-amyloid. A minimum cross-sectional diameter of 2 nm appeared to be necessary for filament stabilization. Bundle and network formation are often observed and are tentatively explained by thermodynamic arguments. The local conformation of the unimer proteins in the filaments remained largely unexplored. Only in one example CD and IR spectroscopy was applied. The analysis disclosed a β-sheet/α-helix transition on de-naturation, as was conjectured before as reason for the Aβ-amyloid formation.