Table 2.
Specific countercharge/S4 residue interactions identified in NaChBac sodium channels.
| Channel | Countercharge locus | S4 locus | Experimental approach | Functional interaction | Reference |
|---|---|---|---|---|---|
| NaChBac | S2 ENC (D60) | R3 (R119) | Cysteine substitution disulfide locking | Activated state | DeCaen et al., 2008 |
| S2 ENC (D60) S2 INC (D70) |
R4 (R122) | Cysteine substitution disulfide locking | Intermediate Activated states |
DeCaen et al., 2009 | |
| S1 ENC (E43) | T0 (T110) R1 (R113) |
Cysteine substitution disulfide locking | Resting state | DeCaen et al., 2011 | |
| S1 ENC (E43) | R2 (R116) R3 (R119) |
Cysteine substitution disulfide locking | Intermediate Activated states |
DeCaen et al., 2011 | |
| S2 ENC (D60) S1 ENC (E43) |
T0 (T110) R1 (R113) R2 (R116) R3 (R119) R4 (R122) |
Cysteine substitution Mutant cycle analysis |
Resting state Intermediate Activated states |
Yarov-Yarovoy et al., 2012 | |
| S1 ENC (E43) | R1 (R113) R2 (R116) |
Mutant cycle analysis | Resting state Activated state |
Paldi and Gurevitz, 2010 |
Residues are identified in extracellular negatively charged (ENC) or intracellular negatively charged (INC) regions of S1–S3 segments, locus in S4 segment, and with interpreted role of their paired interaction.