pH-Dependent Interactions Guide the Folding and Gate the Transmembrane Pore of the β-Barrel Membrane Protein OmpG

摘要: The physical interactions that switch the functional state of membrane proteins are poorly understood. Previously, pH-gating conformations β-barrel forming outer protein G (OmpG) from Escherichia coli have been solved. When pH changes neutral to acidic flexible extracellular loop L6 folds into and closes OmpG pore. Here, we used single-molecule force spectroscopy structurally localize quantify associated with pH-dependent closure. At pH, detected a interaction at L6. This changed (un)folding β-strands 11 12, which connect All other within were unaffected by in pH. These results provide quantitative mechanistic explanation how change folding peptide gate transmembrane They further demonstrate stability is optimized so modify only those necessary