Small-angle neutron and X-ray scattering analysis of the supramolecular organization of rhodopsin in photoreceptor membranes

Publication date: Available online 30 May 2019Source: Biochimica et Biophysica Acta (BBA) - BiomembranesAuthor(s): Tatiana B. Feldman, Oleksandr I. Ivankov, Alexander I. Kuklin, Tatiana N. Murugova, Marina A. Yakovleva, Olga A. Smitienko, Irina B. Kolchugina, Adam Round, Valentin I. Gordeliy, Alexander V. Belushkin, Mikhail A. OstrovskyAbstractThe supramolecular organization of the visual pigment rhodopsin in the photoreceptor membrane remains contentious. Specifically, whether this G protein-coupled receptor functions as a monomer or dimer remains unknown, as does the presence or absence of ordered packing of rhodopsin molecules in the photoreceptor membrane. Completely opposite opinions have been expressed on both issues. Herein, using small-angle neutron and X-ray scattering approaches, we performed a comparative analysis of the structural characteristics of the photoreceptor membrane samples in buffer, both in the outer segment of photoreceptor cells, and in the free photoreceptor disks. The average distance between the centers of two neighboring rhodopsin molecules was found to be ~5.8 nm in both cases. The results indicate an unusually high packing density of rhodopsin molecules in the photoreceptor membrane, but molecules appear to be randomly distributed in the membrane without any regular ordering.Graphical abstract

Source: Biochimica et Biophysica Acta (BBA) Biomembranes - May 30, 2019 Category: Biochemistry Source Type: research