Spectrum determination of the six individual purified rhodopsins from H. marismortui. (A) Group photo of all six rhodopsins purified from E. coli dissolved in MES buffer containing 0.05% n-dodecyl-β-d-maltoside, pH 5.8. From left to right, HmBRI, HmHR, HmSRI, HmSRII, HmBRII, and HmSRM. (B) Absorbance spectrum and absorbance peak of each rhodopsin. AU, arbitrary units.