  It is well established that amyloid fibril solubility is protein specific,
but how solubility depends on the interactions between the fibril building
blocks is not clear. Here we use a simple protein model and perform Monte Carlo
simulations to directly measure the solubility of amyloid fibrils as a function
of the interaction between the fibril building blocks. Our simulations confirms
that the fibril solubility depends on the fibril thickness and that the
relationship between the interactions and the solubility can be described by a
simple analytical formula. The results presented in this study reveal general
rules how side-chain side-chain interactions, backbone hydrogen bonding and
temperature affect amyloid fibril solubility, which might prove a powerful tool
to design protein fibrils with desired solubility and aggregation properties in
general.
