Figure 5.

A model for poly(Gln) aggregate nucleation and extension. In the model, nucleation consists of an unfavorable transition (step a) from an extended, statistical coil state to a compact state corresponding to the aggregation nucleus. The elongation process consists of an initial binding (step b) of the nucleus to an extended conformation monomer, followed by a consolidation of structure (step c) that generates a new binding site for monomer. The resulting dimeric species binds another extended chain monomer (step d) to continue the process.