Fig 5.

Purified MMAR_0617-His shows channel activity in lipid bilayer experiments. (A) Silver-stained SDS-PAGE gel containing Ni-NTA-purified MMAR_0617-His in 1% Triton X-100 (T100) before (−) and after gel filtration chromatography. Obtained fractions 20, 21, 22, and 33 (negative control) were TCA precipitated before loading. A background signal of ∼15 kDa was observed in all fractions, which likely represents coprecipitated T100. MMAR_0617 is indicated by an asterisk, and the fraction used for single-channel activity recordings is marked by an arrow. (B and C) Single-channel activity recordings representative for three biological replicates. Experimental conditions were 1 M KCl, 10 mM HEPES, pH 7.4, at room temperature. (B) Ionic currents through a single channel at −100 mV and +100 mV. At −100 mV, the channel exists in one open conductance state, whereas at +100 mV, the channel fluctuates between different conductance states. (C) Corresponding amplitude histograms.