Fig. 5. Characterization of a Tic110 ΔN mutant. (A) Circular dichroism spectrum of the ΔN mutant Tic110 solved in 2% N-decyl-β-d-maltopyranoside and 50 mM K_iPO₄ pH 7.2. (B) Current traces from a bilayer containing multiple copies of the channel formed by the ΔN mutant Tic110. At both sides of the membrane, 250 mM KCl, 2 mM CaCl₂ and 10 mM MOPS–Tris pH 7.2 were present. With different positive and negative membrane potentials, subconductance levels of the ΔN mutant channel were rarely observed. (C) Current–voltage relationship of a fully open single ΔN mutant channel. The trans and the cis chamber symmetrically contain 250 mM KCl. The values were determined on average of five independent bilayers. The slope conductance of 520 ± 10 pS indicates a high conductance channel.