Importance of the Subunit–Subunit Interface in Ferritin Disassembly: A Molecular Dynamics Study

Ferritin is a spherical cage-like protein that is useful for loading large functional particles for various applications. To our knowledge, how pH affects the interfaces inside ferritin and the mechanism of ferritin disassembly is far from complete. For this article, we conducted a series of molecular dynamics simulations (MD) at different pH values to study how interfaces affect ferritins' stability. It is shown that dimers are stable even at extremely low pH (pH 2.0), indicating that the dimer is the essential subunit for disassembly, and the slight swelling of the dimer resulting from monomer rotation inside a dimer is what triggers disassembly. During ferritin disassembly, there are two types of interfaces involved, and the interface between dimers is crucial. We also found that the driving forces for maintaining dimer stability are different when a dimer is inside ferritin and in an acidic solution. At low pH, the protonation of residues can lead to the loss of the salt bridge and the hydrogen bond between dimers, resulting in the disassembly of ferritin in an acidic environment. The above simulations reveal the possible mechanism of ferritin disassembly in an acidic solution, which can help us to design innovative and functional ferritin cages for different applications.