Molecular dynamics investigation of Human Haemoglobin Tetramer stability

Recent molecular dynamics (MD) simulations of human hemoglobin (Hb), the paradigmatic system for cooperativity in proteins, give results in disagreement with experiment. It is known that Hb is a tetramer with two quaternary structures (T and R). Although experiments have shown that the unliganded (T0) and liganded (R4 ) tetramers are stable in solution, the published MD simulations of T0 undergo a quaternary transition to an R-like structure. We will show that T0 is stable only when the periodic solvent box used contains several times more water molecules than the standard size for such simulations.

To be published soon