Figure 4.

HrpZ_Psph and related HrpZ_Pst and HrpZ_Pss trigger ion-current fluctuations in planar lipid bilayers. (A) Protein from E. coli contaminants was prepared as described in Materials and Methods; purified recombinant HrpZ_Psph (B), HrpZ_Pst (C), or HrpZ_Pss (D) was added to the cis-aqueous solution of the bilayer cuvette, and the induced current traces were recorded. In B, HrpZ_Psph-induced traces were recorded at different membrane potentials, as indicated. Electrolyte solutions (cis/trans) contained 100 mM KCl and 10 mM Hepes, pH 7.0. Dashed lines indicate different open states. c, closed, o₁-o₃, open states. Note different y axes in A–D.