Table 1. Characterization of single cysteine substitution mutants P107C-R135C on the background of the basal mutant (C140A/167A/185A/222A264A/316A).
| Mutants | Chromophoreλmax (nm) | A280/A500 * | Meta II decay(t1/2, min) |
| WT | 500 | 1.6 | 14.7 |
| Basal mutant | 495 | 1.7 | 41 |
| P107C | - | - | - |
| T108C | 495 | 1.9 | 16.3 |
| G109C | 495 | 2.4 | 16 |
| N111C | - | - | - |
| L112C | 495 | 1.8 | 15 |
| E113C | 380 | 2.0# | - |
| G114C | - | - | - |
| F115C | 493 | 2.0 | 13 |
| F116C | 497 | 1.7 | 16 |
| A117C | 486 | 1.8 | 34 |
| T118C | 480 | 2.0 | 16.4 |
| L119C | 497 | 1.9 | 44.5 |
| G120C | 494 | 1.9 | 40 |
| G121C | 485 | 1.8 | 1.8 |
| E122C | 490 | 1.75 | 38 |
| I123C | 495 | 1.9 | 27 |
| A124C | - | - | - |
| L125C | - | - | - |
| W126C | - | - | - |
| S127C | 496 | 1.8 | 46 |
| L128C | - | - | - |
| V129C | 496 | 1.7 | 42 |
| V130C | 496 | 1.7 | 35 |
| L131C | 495 | 1.7 | 37 |
| A132C | 494 | 1.7 | 20 |
| I133C | 495 | 1.8 | 29 |
| E134C | - | - | - |
| R135C | 492 | 2.5 | 42 |
| R135C | 492 | 2.5 | 42 |
*The UV/Vis absorbance spectral ratios were determined after elution from the immunoaffinity cloumn at pH 6.0.
- The purified mutants P107C, N111C, G114C, A124C, L125C, W126C, L128C, and E134C did not form rhodopsin-like chromophore.
#
the ratio of rhodopsin mutant E113C was 280â¶380.