ABSTRACT
Protofibril formation of barstar is independent of initial protein concentration in the tested concentration range. This chapter presents the amyloid formation of phosphoglycerate kinase, a pseudo wild-type of barstar and the Syrian hamster prion protein SHaPrP90-232 in vitro. Elevated temperatures were necessary to start amyloid formation of barstar, whereas misfolding of SHaPrP90-232 could be achieved by addition of denaturants such as GuHCl. The critical oligomers represent a pre-aggregated state of proteins which has to be populated to allow further growth to fibrillar states. In all cases low pH was applied and appropriate amounts of salt were added to screen intermolecular electrostatic repulsion between the protein molecules. The oligomer distribution of SHaPrP90-232 is very heterogeneous with an annular-shaped octamer as smallest product.
