Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.01.278481v1?rss=1 Authors: Koloteva-Levine, N., Marchante, R., Purton, T. J., Hiscock, J. R., Tuite, M. F., Xue, W.-F. Abstract: Amyloid seeds are nanometre-sized protein particles that accelerate amyloid assembly, as well as propagate and transmit the amyloid protein conformation associated with a wide range of protein misfolding diseases. However, seeded amyloid growth through templated elongation at fibril ends cannot explain the full range of molecular behaviours observed during cross-seeded formation of amyloid by heterologous seeds. Here, we demonstrate that amyloid seeds can accelerate amyloid formation via a surface catalysis mechanism without propagating the specific amyloid conformation associated with the seeds. This type of seeding mechanism is demonstrated through quantitative characterisation of the cross-seeded assembly reactions involving two non-homologous and unrelated proteins: the human A{beta}42 peptide and the yeast prion-forming protein Sup35NM. Our results suggest experimental approaches to differentiate seeding by templated elongation from non-templated amyloid seeding, and rationalise the molecular mechanism of the cross-seeding phenomenon as a manifestation of the aberrant surface activities presented by amyloid seeds as nanoparticles. Copy rights belong to original authors. Visit the link for more info