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

• Alternative names: Sensory rhodopsin-2 (SR-2, NpSRII)
• UniProt number: P42196
• Protein class: 7-transmembrane protein
• Organism: Natronomonas pharaonis (Natronobacterium pharaonis)
• 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 500 nm: 45500 M⁻¹cm⁻¹; Extinction coefficient at 590 nm: 54000 M⁻¹cm⁻¹
• Activity: Binding of ligand all-trans retinal, covalently bound to a lysine residue
• Evaluation of UV-VIS spectrum: absorbance ratio 280/500 nm = 2.8
• 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.