Table 1.
Group conservation of small and weakly polar residues at the helix-helix interface of all FNT channelsa
| Residueb | Location in the channel | Residues in the positionc | Conservation (%)d |
|---|---|---|---|
| A38 (TM1) | TM1-TM3 interface | A(46), S, G | 98.2 |
| A41 (TM1) | TM1-Ω interface | A(81), G, S | 99.2 |
| G42 (TM1) | TM1-TM3 interface | G(95), C, S | 99.6 |
| S46 (TM1) | TM1-TM3 interface | G(38), A, S, T | 97.5 |
| A48 (TM1) | TM1-TM2a interface | G(44), A(31), S, T | 95.6 |
| G72 (TM2a) | TM2a-TM5a interface | G(43), A(36), S | 89.8 |
| G78 (TM2a) | TM1-TM2a interface | G(78), A, S | 99.7 |
| G120 (TM3) | TM1-TM3 interface | G(71), A, S, C, T | 87.3 |
| G124 (TM3) | TM1-TM3 interface | G(99) | 99.9 |
| A125 (TM3) | TM1-TM5b interface | A(45), G, S, T, C | 97.4 |
| V129 (TM3) | TM1-TM5b interface | A(62), G, S, C, T | 76.8 |
| G168 (TM4) | TM4-TM6 interface | G(69), A, S | 100.0 |
| C176 (TM4) | TM4-TM6/Ω interface | C(55), A, S, G, T | 89.5 |
| A178 (TM4) | TM4-TM5a interface | A(60), S, G | 79.9 |
| G220 (S-loop) | TM1-TM5b interface | G(42), S, A, T | 78.8 |
| G261 (TM6) | TM4-TM6 interface | G(99) | 99.4 |
| G265 (TM6) | TM4-TM6 interface | G(95), S, A | 99.9 |
| G266 (TM6) | Ω-TM6 interface | G(97), A | 100.0 |
| G271 (TM6) | Ω-TM6 interface | G(56), A, T, S, C | 94.7 |
aAll 2206 FNT channels from bacteria, archaea and eukaryotes were considered for this analysis
bResidue numbers correspond to that of formate channel structure as available in the PDB ID: 3KCU. Occurrence of these residues in the transmembrane segments or the functionally important loop region is also provided
cPercentage conservation of the most frequently observed residue(s) is indicated in brackets
dPercentage conservation as observed in all 2206 FNT channels