FIG 6.
Effect of various sizes of polyethylene glycol on fonticins. (A) Representative current traces of fonticin single pores that were unblocked (control) and blocked by PEG 1000, 3350, and 8000. All measurements were performed at a constant potential of 50 mV in 1 M NaCl, 10 mM Tris, and 8 mM MgCl2, pH 7.3, with E. coli lipids. Fonticin pores were blocked by the presence of 20% (wt/vol) PEG 1000, 3350, or 8000, which was added to the cis (gray current traces) or trans (blue current traces) side of the cuvette. (B) For each PEG size and side of PEG addition (cis or trans), a conductance histogram (n > 60) was constructed using kernel density estimation (rectangular kernel with 50 pS width). The cis side addition of PEG is shown in gray and the trans side addition in blue. The control histogram of unblocked fonticin pores was fitted to a Gaussian function with its center at 785 pS.