Table 1. Absorption maximum and pKa value of wild-type and various GR mutants.
Opsin type | GR WT | GR D121N | GR E132D | GR E132Q |
λmax (nm) | pH 4: 549 | pH 4: 558 | pH 4: 550 | pH 4: 561 |
pH 7: 544 | pH 7: 560 | pH 7: 544 | pH 7: 550 | |
pH 9: 543 | pH 9: 563 | pH 9: 540 | pH 9: 540 | |
pKa | 5.9 | 6.0 | 5.4 | 4.2 |
9.2 | 11.0 | 6.1 | 7.2 |