TABLE 1.
Conductance and Glc-1-P induced zero current potential shift of the OEP40 channel at different ionic strength
Conductance values (G) were calculated from the linear slope conductance of current-voltage sweeps (average from n ≥3 sweeps) at the low conductance site. PGlc-1-P(app) is the relative apparent permeability (PGlc-1-P− = X: PK+ = PNa+ = 4: PCl− = 1) calculated for the tri-ionic conditions using the GHK equation (see supplemental Methods). Because in the OEP40-containing bilayers with 100 mm KCl (cis) and 100 mm NaCl (trans) no zero current shift was observed, we can set PK+ = PNa+.
| cKCl (cis) | cKCl(trans) | cGlc-1-P(cis) | ḡ | Vrev | PGlc-1-P(app) |
|---|---|---|---|---|---|
| mm | mm | mm | pS | mV | |
| 250 | 250 | 0 | 325 ± 38 | 0 | − |
| 250+ | 250 | 6 | 380 ± 23 | −6.7 | 48 |
| 12 Na+ | |||||
| 100 | 100 | 0 | 127 ± 1.8 | 0 | − |
| 100+ | 100 | 6 | 123 ± 3.0 | −11.9 | 47 |
| 12 Na+ | |||||
| 20 | 20 | 0 | 30 ± 4.6 | 0 | − |
| 20+ | 20 | 6 | 26.7 ± 0.6 | −26.9 | 49 |
| 12 Na+ |