Sensory rhodopsin-2 (SR-2) is a 7-transmembrane helice protein that acts as a phototaxis receptor in archaebacteria.

• Alternative names: Sensory rhodopsin-2 (SR-2, NpSRII)
• UniProt Number: P71411
• Protein class: seven-transmembrane protein
• Organism: Halobacterium salinarum S9
• Sequence, explained: wild-type sequence, full-length, 6× his-tag
• Affinity tags:His-tag (C-terminus)
• Expression Host: E.coli
• Buffer composition: 4 M NaCl, 50 mM MES pH 6.0, 0.03% dodecyl maltoside (DDM)
• Purified via: PureCube Ni-NTA Agarose
• Absorbance: Extinction coefficient at 497 nm: 48000 M⁻¹cm⁻¹
• Extinction coefficient at 590 nm, 54000 M⁻¹ cm⁻¹
• Activity: Binding of ligand all-trans retinal, covalently bound to a lysine residue. Evaluation of UV-VIS spectrum: absorbance ratio 280/497 nm = 1.7 (additional vibronic bands at 460 and 420 nm)
• Function: Photoreceptor protein undergoing a photocycle, Retinal protein, photophobic phototaxis receptor

Due to sensory rhodopsin-2's 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.