Table 4.
Subfamily-specific conservation in FNT channelsa
| Residueb | FocA | FdhC | NirC-α | NirC-β | NirC-γ | HSC | YfdC-α | YfdC-β |
|---|---|---|---|---|---|---|---|---|
| F202c (TM5a) | F (100) | F (99.6) | F (100) | F (100) | F (100) | F (100) | V, I, M (99.7) | I, M, L, V (100) |
| A212c (TM5b) | A (100) | A (93.4) | V (100) | A (100) | A (82.7) | A (100) | V (71.5) | V, I, L (73.5) |
| L79d (TM2a) | L, V, I (99) | L, I (93.4) | F, Y (98.1) | L (100) | L (99.4) | L, V, I (96.0) | F, Y (100) | F (73.5) |
| F90e (Ω-loop) | F (100) | V, L, I (86.3) | V, L (90.9) | F, Y (100) | --- | F (91.7) | F, Y (99.7) | F (100) |
| N172e (TM4) | N (100) | N (99.6) | N (100) | N (100) | N (99.4) | N (96.4) | G (99.7) | G (99.0) |
| G86 (Ω-loop) | G (99.3) | G (100) | G (91.9) | G (100) | N, Q (76) | G, S (95.6) | R, H, D (81.2) | R, H, K (75.5) |
| S92 (Ω-loop) | S (100) | G, S (100) | G (99.0) | G (100) | S, G (100) | G, S, A (100) | E (100) | E (90.2) |
| T93 (Ω-loop) | T, S (100) | N (91.3) | V (84.8) | H (98.7) | N (95.5) | N (88.9) | N (93.1) | --- |
| K100 (TM2b) | K, R (79.9) | A, S, G (99.6) | A, S, G (99.5) | G, A (100) | G, A, S (100) | G, S, A, T (97.2) | P (75.1) | --- |
| E208 (S-loop) | E (100) | Q (83) | E (100) | E (100) | E (99.4) | E, D (96.8) | A, S, T (75.6) | --- |
| T34 (TM1) | T, A, S (94.3) | L, M, I, V (78.8) | --- | F (100) | Y, F (98.9) | F, Y (98.8) | L, I (93.9) | L, I, V, M (94.1) |
| L37 (TM1) | L, M (81.2) | L (83.0) | R, K (95.2) | G, S, A (96.2) | R, K (98.9) | --- | S, A (96.4) | T, S (97.1) |
| N113 (TM3) | N (77.2) | N (90.9) | N (74.3) | V, I (96.2) | V, L, I, M (99.4) | --- | L, V, I, M (85.6) | L, I, V, (99.0) |
| L167 (TM4) | L (100) | S (75.1) | K, R (94.8) | K, R (100) | R, K, E, D (98.3) | R, K (95.6) | --- | --- |
| N254 (TM6) | N (100) | N (97.9) | N (100) | N (100) | N, Q (72.6) | N (89.3) | F, Y (96.1) | F, W (74.5) |
aPercentage conservation residues for each subfamily is given in brackets
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 regions is also indicated
cPart of the central constriction site; dPart of the cytoplasmic slit in the closed state; ePart of the cytoplasmic slit in the open state