| Project/Area Number |
26650119
|
|---|
| Research Category |
Grant-in-Aid for Challenging Exploratory Research
|
| Allocation Type | Multi-year Fund |
|---|
| Research Field |
Animal physiology/Animal behavior
|
|---|
| Research Institution | Kyoto University |
|---|
Principal Investigator |
|
|---|
| Project Period (FY) |
2014-04-01 – 2016-03-31
|
| Project Status |
Completed (Fiscal Year 2015)
|
| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,000,000、Indirect Cost: ¥900,000)
Fiscal Year 2015: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
|
|---|
| Keywords | 視物質 / 視細胞 / 暗ノイズ / 生化学的方法 / 分子進化 / 生化学的手法 |
|---|
| Outline of Final Research Achievements |
Low dark noise is a prerequisite for rod cells, which mediate our dim-light vision. The low dark noise is achieved by the extremely stable character of the rod visual pigment, rhodopsin, which evolved from less stable cone visual pigments. We have developed a biochemical method to quickly evaluate the thermal isomerization rate of the chromophore in visual pigments. Using an isomerization locked chromophore, we confirmed that thermal isomerization rate of the chromophore in rhodopsin is about 1/1000 of that of cone visual pigment and identified two critical residues (E122 and I189) in the chromophore binding pocket which account for the extremely low thermal activation rate of rhodopsin. Furthermore, we found that anura blue-sensitive cone visual pigment expressed in green rods acquired the low thermal isomerization rate of the chromophore by the specific mutation during the molecular evolution, which led to optimization for scotopic vision.
|
