SPIN-LABEL STUDY OF APOMEMBRANES AND PURPLE MEMBRANES

Three spin-labelled fatty acids were used to detect the dynamics of lipid bilayer of apomembranes and purple membranes. It was found that ESR spectra of spin labels bound to apomembranes showed a temperature-induced changes rather similar to those seen with purple membranes. At the same time, however, the values of hyperfine splitting parameter 2T(m) were lower as compared to purple membranes. The results pointed out that the removal of the retinal from purple membranes affects the dynamics of lipid bilayer and apomembranes were more rigid structure than those of purple membranes.