FIGURE 4.

Activation of N117H/N167H MscS is decreased by adding ZnCl₂. (A) Representative patch clamp recordings from the same patch before and after addition of 1 mM ZnCl₂ to the bath. The recordings are from the E. coli MJF465 strain; lower traces: applied negative pressure. Channels without His-tag were used in this experiment. (B) Pressure-activated current significantly decreased in N117H/N167H MscS with ZnCl₂ treatment (mean ± SEM, n = 6; ^∗∗∗p < 0.001). (C) Left: single-channel openings recorded from histidine substitutions after ZnCl₂ treatment (dashed horizontal lines indicate closed states); right: count vs. amplitude histograms. (D) Conductance of histidine substitutions after ZnCl₂ treatment determined at 20 mV membrane potential (mean ± SEM, n = 6).