Channelrhodopsin 1 is a 7-transmembrane protein that acts as a light-driven cation channel in eukaryotic green algae. Due to its covalently bound colored ligand, it is ideal for use as a control membrane protein, for example for crystallization assays and biochemical/biophysical experiments. We provide channelrhodopsin 1 of high purity, purified from yeast as a his-tagged protein.
Figure 1: SDS-PAGE of channelrhodopsin 1 from C. augustae.
Figure 2: Absorbance spectrum of channelrhodopsin 1 from C. augustae.
Features
| Protein | Channelrhodopsin 1 (CaChR1) |
| UniProt number | G8HKA1 |
| Protein class | 7-transmembrane protein |
| Organism | Chloromonas augustae (Chlamydomonas augustae) |
| Sequence | wild-type sequence, N-terminal membrane-spanning domain (362 of 715 aa), 10x His-tag (red)
MDTLAWVARE LLSTAHDATP ATATPSTDHS TPSTDHGSGE TFNVTITIGG GHHGGHAGPV DNSIVIGGID GWIAIPAGDC YCAGWYVSHG SSFEATFAHV CQWSIFAVCI LSLLWYAWQY WKATCGWEEV YVCCIELVFI CFELYHEFDS PCSLYLSTAN IVNWLRYSEW LLCCPVILIH LSNVTGLSDD YGRRTMGLLV SDIATIVFGI TAAMLVSWPK IIFYLLGFTM CCYTFYLAAK VLIESFHQVP KGICRHLVKA MAITYYVGWS FFPLIFLFGQ SGFKKISPYA DVIASSFGDL ISKNMFGLLG HFLRVKIHEH ILKHGDIRKT THLRIAGEEK EVETFVEEED EDHHHHHHHH HH
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| Affinity tags | His-tag (C-terminus) |
| Size | 362 amino acids; 40,661 Da |
| Expression system | Pichia pastoris (yeast) |
| Purified via | PureCube Ni-NTA Agarose |
| Buffer | 100 mM NaCl, 20 mM HEPES pH 7.4, 0.03% dodecyl maltoside (DDM) |
| Purity (SDS-PAGE) | >98%, see Fig. 1 |
| Absorbance | Extinction coefficient at 518 nm: 36,000 M-1 cm-1. |
| Absorbance | Extinction coefficient at 590 nm: 54,000 M-1 cm-1. |
| Activity | Binding of ligand all-trans retinal, covalently bound to a lysine residue. Evaluation of UV-VIS spectrum: absorbance ratio 280 nm / 518 nm = 2.2 (additional vibronic band at 480 nm) |
| Function | Photoreceptor protein undergoing a photocycle, Retinal protein, light-driven cation channel |
| Literature references | - Hou, Sing‐Yi, et al. "Diversity of Chlamydomonas channelrhodopsins." Photochemistry and photobiology 88.1 (2012): 119-128.
- Muders, Vera, et al. "Resonance Raman and FTIR spectroscopic characterization of the closed and open states of channelrhodopsin-1." FEBS letters 588.14 (2014): 2301-2306.
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