Schematic Illustration (IMAGE) Tokyo Institute of Technology Caption Based on the HS-AFM observations, we propose that the freely moving tails of the monomers of the yeast prion protein Sup35 are incorporated into the fibril ends, and then the structural conversions to cross-β structures gradually occur. Credit Tokyo Tech Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.