Sensory rhodopsin-2 (SR-2) is a 7-transmembrane protein that acts as a phototaxis receptor in archaebacteria. Due to its covalently bound colored ligand, SR-2 is ideal for use as a control membrane protein, for example for crystallization assays and biochemical/biophysical experiments. We provide SR-2 of high purity, purified from E. coli as a His-tagged protein.
Figure 1: SDS-PAGE of sensory rhodopsin-2 from N. pharaonis.
Figure 2: Absorbance spectrum of sensory rhodopsin-2 from N. pharaonis.
Features
| Protein | Sensory rhodopsin-2 (SR-2, NpSRII) |
| UniProt number | P42196 |
| Protein class | 7-transmembrane protein |
| Organism | Natronomonas pharaonis (Natronobacterium pharaonis) |
| Sequence | wild-type sequence, full-length, 7x His-tag (red)
MVGLTTLFWL GAIGMLVGTL AFAWAGRDAG SGERRYYVTL VGISGIAAVA YVVMALGVGW VPVAERTVFA PRYIDWILTT PLIVYFLGLL AGLDSREFGI VITLNTVVML AGFAGAMVPG IERYALFGMG AVAFLGLVYY LVGPMTESAS QRSSGIKSLY VRLRNLTVIL WAIYPFIWLL GPPGVALLTP TVDVALIVYL DLVTKVGFGF IALDAAATLR AEHGESLAGV DTDAPAVADH HHHHHH
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| Affinity tags | His-tag (C-terminus) |
| Size | 246 amino acids; 26,315 Da |
| Expression system | E.coli |
| Purified via | PureCube Ni-NTA Agarose |
| Buffer | 4 M NaCl, 300 mM NaCl, 50 mM MES pH 6.0, 0.03% dodecyl maltoside (DDM) |
| Purity (SDS-PAGE) | >98%, see Fig. 1 |
| Absorbance | Extinction coefficient at 500 nm: 45,500 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 / 500 nm = 2.8 |
| Function | Photoreceptor protein undergoing a photocycle, Retinal protein, photophobic phototaxis receptor |
| Literature references | - Gordeliy, Valentin I., et al. "Molecular basis of transmembrane signalling by sensory rhodopsin II–transducer complex." Nature 419.6906 (2002): 484.
- Orekhov, Philipp, et al. "Sensory rhodopsin I and sensory rhodopsin II form trimers of dimers in complex with their cognate transducers." Photochemistry and photobiology 93.3 (2017): 796-804.
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