OmpW of Caulobacter crescentus Functions as an Outer Membrane Channel for Cations
Fig 4
A. Single-channel recordings of a PC/n-decane membrane in the presence of purified OmpW of C. crescentus. The aqueous phase contained 1 M KCl and 20 ng ml−1 OmpW dissolved in 1% Genapol. The applied membrane potential was 20 mV; T = 20°C. B. Histogram of the probability P(G) for the occurrence of a given conductivity unit observed with membranes formed of PC/n-decane in the presence of OmpW of C. crescentus. P(G) is the probability that a given conductance increment G is observed in the single-channel experiments. It was calculated by dividing the number of fluctuations with a given conductance increment by the total number of conductance fluctuations. The aqueous phase contained 1 M KCl and about 20 ng/ml OmpW. The applied membrane potential was 20 mV; T = 20°C. A Gaussian function was applied to the histogram and the maximum of the curve was taken as average single-channel conductance. It was 117 (± 19) pS for 95 single-channel events.