The TSE shows strong interactions between the incoming monomer and the fibril end with approximately 30% of the monomer sequence being engaged in its full set of fibrillar contacts, while 50% is fully detached, and the remaining 20% make fractional interactions. Two main regions, residues 4-16 and 49-62, are rigidly attached to the fibril end while residues 16 to 48 and the N-and C-terminal regions of the incoming monomer are disordered (Figure and). Single residues in the disordered regions maintain large fractions of their fibril and inter-chain contacts (residues E4, Y12, D13, Y14, I29, L30 and F69). These fractional contacts could play a crucial role in guiding the monomer towards its ultimate conformation on the fibril template.