RADICAL CHANGES IN BETA-AMYLOID FORM AND FUNCTION

A growing body of evidence supports the nucleation hypothesis of fibri llar amyloid formation. In this article, it is hypothesized that the f ibrils formed with human A beta, rodent A beta, and a mixture of the t wo peptides may form nearly identical physical structures with clearly different biological activities. Data is reported supporting the conc ept that a specific ''strain'' of nucleation seed could impart a new s tructure on a growing amyloid fibril, thereby changing its biological activity. The data that the biological activities of specific prion st rains have a basis in strain-specific structure have been supported ex perimentally.