Table 1.
Amino acid sequences of the C-helix in various microbial rhodopsins
| 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 | 91 | 92 | 93 | 94 | 95 | 96 | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BR | H+ pump | R | Y | A | D | W | L | F | T | T | P | L | L | L | L | D |
| PR | H+ pump | R | Y | I | D | W | L | L | T | V | P | L | L | I | C | E |
| KR2 | Na+ pump | R | Y | L | N | W | S | I | D | V | P | M | L | L | F | Q |
| FR | Cl− pump | R | Y | G | N | W | T | I | T | V | P | I | L | L | T | Q |
| pHR | Cl− pump | R | Y | L | T | W | A | L | S | T | P | M | I | L | L | A |
| CrCCR1 | cation channel | R | Y | A | E | W | L | L | T | C | R | V | I | L | I | H |
| CrCCR2 | cation channel | R | Y | A | E | W | L | L | T | C | P | V | I | L | I | H |
| CaCCR1 | cation channel | R | Y | S | E | W | L | L | C | C | P | V | I | L | I | H |
| MvCCR1 | cation channel | R | Y | M | E | W | L | M | T | C | P | V | I | L | I | A |
| GtCCR1 | cation channel | P | Y | L | D | Y | A | T | T | C | P | L | L | T | L | D |
| GtCCR2 | cation channel | P | Y | V | D | Y | C | T | T | C | P | L | L | T | L | D |
| GtCCR3 | cation channel | K | Y | L | D | Y | L | F | T | C | P | L | L | T | I | D |
| GtCCR4 | this study | K | Y | L | D | Y | I | F | T | C | P | I | L | T | L | D |
| GtACR1 | anion channel | R | M | A | S | W | L | C | T | C | P | I | M | L | G | L |
| GtACR2 | anion channel | R | M | A | S | W | L | C | T | C | P | I | M | L | G | Q |
Abbreviations: BR, bacteriorhodopsin; PR, proteorhodopsin; KR2, Krokinobacter eikastus rhodopsin 2; FR, Fulvimarina rhodopsin; pHR, Natronomonas pharaonis halorhodopsin; CrCCR1 and 2, cation channelrhodopsin (ChR) 1 and 2, respectively from Chlamydomonas reinhardtii; CaCCR1, cation ChR1 from Chlamydomonas augustae; MvCCR1, cation ChR1 from Mesostigma viride; GtCCR1, 2, 3 and 4, cation ChR1, 2, 3 and 4, respectively from Guillardia theta; GtACR1 and 2, anion ChR1 and 2, respectively from G. theta. The numbering scheme corresponds to the position of BR.