Detailed Analysis of the Energy Barriers for Amyloid Fibril Growth

The free energy barriers that determine the kinetics of the growth of amyloid fibrils have been measured for a series of peptides and proteins using a quartz crystal microbalance. The results indicate that the enthalpic contribution to the free energy barrier is invariably unfavorable and correlates with the size and structure of the soluble parent polypeptide, whereas the entropic contribution is favorable and linked to the hydrophobicity of the peptide sequence.