The Impact of Hydrodynamic Interactions on Protein Folding Rates Depends on Temperature

Hydrodynamic interactions (HI) arise by the exchange of momentum between solvent particles and the particles immersed in solvent effectively coupling the movement of the entire system. However, the extent of the impact of HI on protein folding kinetics is controversial. Using a minimalist coarse-grained computer model and the theoretical framework of the Energy Landscape Theory (ELT) for protein folding, we revealed the effects of HI on the folding rates of two proteins with distinctive topologies: a 64-residue α/β chymotrypsin inhibitor 2 (CI2) protein, and a 57-residue β-barrel α-spectrin src-Homology 3 domain (SH3) protein. We find that the effect of HI on protein folding is temperature dependent. At a temperature greater than the folding temperature, HI drags the polymeric chain away from collapsing, resulting in a retarded folding rate. Conversely, at a temperature lower than the folding temperature, HI facilitates folding rates depending on the topology of a protein. Our investigation provides a general explanation of the impact of HI on protein folding.