Engineered Oligomerization State of OmpF Protein through Computational Design Decouples Oligomer Dissociation from Unfolding

摘要: Biogenesis of β-barrel membrane proteins is a complex, multistep, and as yet incompletely characterized process. The bacterial porin family perhaps the best-studied protein among that allows diffusion small solutes across outer membrane. In this study, we have identified residues contribute significantly to protein–protein interaction (PPI) interface between chains F (OmpF), trimeric porin, using an empirical energy function in conjunction with evolutionary analysis. By replacing these through site-directed mutagenesis either energetically favorable or substitutions do not occur natural proteins, succeeded engineering OmpF mutants dimeric monomeric oligomerization states instead state. Moreover, our results suggest proceeds series interactions involving two distinct regions extensive PPI interface: monomers interact form dimer near G19. This then interacts another monomer G135 trimer. We found perturbing G19 formation only. Thermal denaturation designed mutant suggests oligomer dissociation can be separated from process unfolding. Furthermore, conserved site G57 G59 important for might provide essential scaffold PPIs.