TABLE 1.

Selectivity of maxi-anion channel for different organic anions and ionic conductivity ratios

Anion	RX (nm)	Erev (mV)	PX/PCl	χ(X)/χ(Cl)
Formate	0.212	−10.6 ± 0.6	0.662 ± 0.014	0.619 ± 0.003
Acetate	0.242	−17.7 ± 1.4	0.502 ± 0.027	0.450 ± 0.003
Propanoate	0.267	−24.1 ± 0.8	0.391 ± 0.011	0.378 ± 0.002
Glutamate	0.345	−46.9 ± 1.3	0.161 ± 0.008	0.266 ± 0.003
Pyruvate	0.271	−16.9 ± 1.7	0.518 ± 0.013	0.428 ± 0.003
Methanesulfonate	0.267	−17.5 ± 0.4	0.506 ± 0.009	0.508 ± 0.002
Gluconate	0.349	−45.9 ± 0.8	0.168 ± 0.005	0.198 ± 0.002
Glucuronate	0.363	−39.7 ± 1.6	0.190 ± 0.013	0.198 ± 0.002
Glucoheptonate	0.393	−40.7 ± 1.4	0.178 ± 0.013	0.153 ± 0.003
Lactobionate	0.487	−53.0 ± 1.3	0.127 ± 0.006	0.094 ± 0.002

R_X is the unhydrated radius calculated as a geometric mean of three dimensions according to the formula R_X = (1/2) (l₁ l₂ l₃)^1/3, where l₁, l₂, and l₃ are ion dimensions estimated from space-filling models (data were taken from Linsdell and Hanrahan, 1998). For E_rev determination, the unitary channel amplitudes were collected at different voltages from at least five different patches, the I–V curves were constructed, and reversal potentials were calculated from polynomial fits (Eqs. 1–3). Ionic conductivities χ(X) were calculated from experimentally measured solution conductivities, as described in Materials and Methods. Each value represents the mean ± SE of five observations.