m_moumit@jncasr.ac.in
Proteins can precipitate from solution by forming either disordered or ordered aggregates. The latter situation, which arises due to the aggregation of partially folded or misfolded proteins, has been a subject of much interest recently. We develop a coarse-grained model to study this phenomenon, considering three possible configurational states for proteins, namely, native state, misfolded state and random coil state.
We consider the nearest neighbour interaction only between the misfold states which will favor aggregation at high concentrations of the protein solution. A phase transition between native/random coil, and misfolded phases occurs, as seen in a mean-field calculation and confirmed by numerical simulations. The native state and random coil state are assumed as one phase because there is a pseudo-transition between them and the misfolded state is the other phase.
We have located the coexistence and the limit of stability of the two
phases by the mean-field study. We also study the distribution of
aggregate size using Monte Carlo simulations.