Table 1.

Translocation channel diameter d and selectivity r of SecYEG and SecYEG-YidC complexes.

	ψr (mV)	r	$\tilde{g}$ (pS/mM)	d (Å)
SecYEG + ribosomes	−7.2 ± 2.3	2 ± 0.5	1.6 ± 0.1	8.4 ± 0.5
SecYEG + RNCFtsQ	−6.7 ± 1.1	1.9 ± 0.2	1.7 ± 0.1	8.6 ± 0.5
SecYEG/YidC + ribosomes	−9.2	2.5 ± 0.4	0.9 ± 0.2	5.1 ± 0.6
SecYEG/YidC + RNCFtsQ	−15 ± 3.9	5.3 ± 3.15	1.75 ± 0.1	8.1 ± 0.5

The reversal potential ψ _r was obtained by plotting the single channel current as a function of membrane voltage (Fig. 3b). Anion to cation permeability ratios r (mean ± standard deviation) were calculated according to Eq. 1. $\tilde{g}$ is the single-channel equivalent conductance, which is defined as the ratio of the single channel conductance g and the average ionic strength of solution in both the cis and trans compartments and d is the pore diameter calculated according to Eq. 2.