(A) (B) Clearly resolved separation of individual β-strands along the fibril. (C) Extra density at the interface of adjacent protofilaments between the positively charged lysines K43 and K45 and lysine K58. (D) Hydrophilic region surrounding a tunnel filled with an additional density. (E) Phosphorylation site S87 showing the location of this residue towards the outside of the fibril. (F) Distal loop of a protofilament indicating residues G68, A69 and G93, which may contribute to loop stability. (G) Arrangement of G47 and A78, which may contribute to the interaction between E46 and K80. (H) Interaction between H50 and E57 in the interface region of two protofilaments, which may contribute to the stability of protofilament interaction.