Studies on the temperature effect on bacteriorhodopsin of purple and blue membrane by fluorescence and absorption spectroscopy.

Fluorescence and absorption spectra were used to study the temperature effect on the conformation of bacteriorhodopsin (bR) in the blue and purple membranes (termed as bRb and bRp respectively). The maximum emission wavelengths of tryptophan fluorescence in both proteins at room temperature are 340 nm, and the fluorescence quantum yield of bRb is about 1.4 fold higher than that of bRp.