Abstract

The paper analyzes the literature data concerning the influence of the Triton-X100 detergent on the optical properties of purple membranes and the photocycle of bacteriorhodopsin molecules. The method of changing the sizes of purple membranes fragments by means of treating them with a detergent and subsequent centrifugation is proposed. The control of the detergent effect on the properties of purple membranes was carried out using spectral analysis and AFM microscopy. As a result of the spectral characteristics investigation of bacteriorhodopsin suspensions and films with the addition of Triton-X100, it was found that high concentrations (>4 mM) of detergent cause the destruction of purple membranes and irreversible changes in the structure of bacteriorhodopsin under the influence of temperature and optical radiation. At the same time, at lower concentrations partial solubilisation is observed in which there is a decrease in the size of purple membranes and a significant part of the bacteriorhodopsin molecules retains its unique optical properties. The atomic force microscopy study of fragments of purple membranes treated with detergent Triton-X100 with a concentration of 2.5 mM showed that large fragments are divided into smaller ones, the dimensions of which make up about 1 μm. The use of detergents can influence the size of fragments of purple membranes and thus increase the optical quality of film structures based on bacteriorhodopsin. The disadvantage of this method is  the loss of material in the process of detergent treatment due to the complete solubilization of a large part of the purple membranes

Keywords: detergent, Triton-X100, purple membranes, bacteriorhodopsin, optical microscopy, atomic force microscopy

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