Active, purified Bacteriorhodopsin (Halobacterium salinarum)
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.
Protein
Bacteriorhodopsin (BR, HsBR, bacteriopsin)
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
MLELLPTAVEGVSQAQITGRPEWIWLALGTALMGLGTLYFLVKGMGVSDPDAKKFYAITTL VPAIAFTMYLSMLLGYGLTMVPFGGEQNPIYWARYADWLFTTPLLLLDLALLVDADQGTILA LVGADGIMIGTGLVGALTKVYSYRFVWWAISTAAMLYILYVLFFGFTSKAESMRPEVASTFK VLRNVTVVLWSAYPVVWLIGSEGAGIVPLNIETLLFMVLDVSAKVGFGLILLRSRAIFGEAEA PEPSAGDGAAATSD
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
Hs_Bacteriorhodopsin (500 µg)