Bacteriorhodopsin (BR) is a 7-transmembrane protein that acts as a light-driven proton pump in archaebacteria. Due to its covalently bound colored ligand, BR is widely used as a control membrane protein, for example for crystallization assays and biochemical/biophysical experiments. We provide BR of high purity, prepared as purple membrane patches from Halobacterium salinarum.
Figure 1: SDS-PAGE of bacterio-rhodopsin in purple membrane patches from H. salinarum.
Figure 2: Absorbance spectrum of bacteriorhodopsin in purple membrane patches from H. salinarum.
Features
| Protein | Bacteriorhodopsin (BR, HsBR, bacteriopsin) |
| UniProt number | P02945 |
| Protein class | 7-transmembrane protein |
| Organism | Halobacterium salinarum S9 |
| Sequence | Full-length, wildtype sequence N-terminal signal sequence (underlined) which is mostly absent in the preparation
MLELLPTAVE GVSQAQITGR PEWIWLALGT ALMGLGTLYF LVKGMGVSDP DAKKFYAITT LVPAIAFTMY LSMLLGYGLT MVPFGGEQNP IYWARYADWL FTTPLLLLDL ALLVDADQGT ILALVGADGI MIGTGLVGAL TKVYSYRFVW WAISTAAMLY ILYVLFFGFT SKAESMRPEV ASTFKVLRNV TVVLWSAYPV VWLIGSEGAG IVPLNIETLL FMVLDVSAKV GFGLILLRSR AIFGEAEAPE PSAGDGAAAT SD
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| Affinity tags | None |
| Size (excluding additional elements) | 262 amino acids; 28,256 Da |
| Expression system | Halobacterium salinarum S9 |
| Purified via | Sequential centrifugation |
| Buffer | Purple membrane (PM) patches in H2O, 0.02% NaN3 |
| Purity (SDS-PAGE) | >98%, see Fig. 1 |
| Absorbance | Extinction coefficient at 560 nm: 63,000 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 / 560 nm = 2.3 |
| Function | Photoreceptor protein undergoing a photocycle, Retinal protein, light-driven proton pump |
| Literature references | - Kubicek, Jan, et al. "Controlled in meso phase crystallization–a method for the structural investigation of membrane proteins." PloS one 7.4 (2012): e35458.
- Zscherp, Christian, Ramona Schlesinger, and Joachim Heberle. "Time-resolved FT-IR spectroscopic investigation of the pH-dependent proton transfer reactions in the E194Q mutant of bacteriorhodopsin." Biochemical and biophysical research communications 283.1 (2001): 57-63.
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