Two major stable structures of amyloid-forming peptides: amorphous aggregates and amyloid fibrils

Abstract

A peptide -m, which is a fragment from residue 21 to residue 31 of -microgloblin, is experimentally known to self-assemble and form amyloid fibrils. In order to analyze the conformations of amyloid-forming peptides in the early stage of aggregation, we applied the replica-exchange molecular dynamics method to the system consisting of three fragments of -m. From the analyses concerned with the temperature dependence, we found that there is a clear transition temperature in which the peptides aggregate each other. Moreover, we found that there are two major stable states: One of them is like amyloid fibrils and the other is amorphous aggregates by the free energy analyses.