Mechanistic Explanation of Different Unfolding Behaviors Observed for Transmembrane and Soluble β-Barrel Proteins

摘要: In response to mechanical stress, membrane proteins progress through sequences of major unfolding barriers, whereas soluble usually must overcome only one barrier. To gain insight into these markedly different behaviors, we applied force-probe molecular dynamics simulations and unfolded two β-barrel proteins, the transmembrane outer protein G (OmpG) water-soluble green fluorescent (GFP). The mimic with high precision experiments show that OmpG in absence a GFP circumvent barriers by rotations explore alternative pathways. Embedding lipid restricts this search for pathways forces cross barriers. Likewise, restricting rotation traverse similar manner membrane-embedded OmpG. These results indicate mechanically stressed explain why generally higher stability compared proteins.