|Comment by B. Edward Bondo and Nikolay V. Dokholyan
Kammerer et al. have developed a simplified protein-like model system to study the molecular details of the assembly of protein amyloid structures. Their system consists of a 17-residue peptide, ccβ, which forms native-like coiled-coil structures under ambient conditions, but can be induced to form amyloid fibrils when these conditions are altered. They find that the lag phase and growth phase of amyloid fibril assembly is temperature and concentration dependent and that the addition of preformed aggregates containing β-sheets eliminates the lag phase, suggesting that these peptides aggregate with a nucleation-dependent self-assembly process. By mutating their peptide, they find that interactions between the hydrophobic side chains in the peptides are very important in the rate of assembly of the fibrils. Structural studies allow the authors to attribute this effect to hydrophobic packing of the side chains. The system the authors design appears to be a promising model system to determine some of the driving forces of...