Abstract
Definition of rhodopsin is the retinal-binding membrane protein with the Schiff base linkage at a lysine on the 7th transmembrane helix. However, ~ 600 microbial rhodopsins lack retinal-binding lysine at the corresponding position (Rh-noK) among ~ 5500 known microbial rhodopsins, suggesting that Rh-noK has each functional role without chromophore. Here, we report successful functional recovery of Rh-noK. Two Rh-noKs from bacteria were heterologously expressed in Escherichia coli, which exhibited no color. When retinal-binding lysine was introduced, one of them gained visible color. Additional mutation of the Schiff base counterion further gained proton-pumping activity. Successful engineered functional recovery such as visible color and proton-pump activity suggests that the Rh-noK protein forms a characteristic structure of microbial rhodopsins.
Original language | English |
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Pages (from-to) | 1116-1121 |
Number of pages | 6 |
Journal | Photochemistry and Photobiology |
Volume | 95 |
Issue number | 5 |
DOIs | |
State | Published - 1 Sep 2019 |
All Science Journal Classification (ASJC) codes
- Biochemistry
- Physical and Theoretical Chemistry