Table 2.
Calculated pKashifts due to chloride occupation in Scenand Sint
| Model | ClC | ΔpKa1 |
ΔpKa2 |
||
|---|---|---|---|---|---|
| Closed | Open | Closed | Open | ||
| Model 1 | EcClC | 1.17 | 0.40 | 0.24 | 0.24 |
| CpClC-2 | 0.87 | 0.41 | 0.25 | 0.21 | |
| SF100 | EcClC | 3.04 | 1.05 | 0.02 | 0.22 |
| CpClC-2 | 2.22 | 0.68 | 0.18 | 0.32 | |
ΔpKa1= pKa(Clcen)− pKa(no Cl), pKa shift due to Cl− occupation of Scen and ΔpKa2= pKa(Clcen,in)− pKa(Clcen), pKa shift after additional occupation of Sint by Cl−. Calculated for the open and closed conformation of the gating glutamate. Model 1 considers Eext and Cl− ions only. SF100 considers in addition 100 atoms of the selectivity filter amino acids.