Biophysical Society Thematic Meeting| Lima 2019

Revisiting the Central Dogma of Molecular Biology at the Single-Molecule Level

Poster Abstracts

17-POS Board 17 RHODOPSIN FLUORESCENCE SPECTROSCOPY ANALYSIS PROVIDES NEW INSIGHTS INTO MAMMAL EVOLUTION TO DIURNAL VISION. Miguel Fernandez Sampedro 1,2 ; Neda Razzaghi 1 ; Pere Garriga 1 ; 1 Universitat Politècnica de Catalunya, Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d’Enginyeria Química, Terrassa, Catalonia, Spain 2 Universidad Científica del Sur, Facultad de Ciencias Ambientales, Lima, Peru Visual rhodopsin are G protein-coupled receptors located in the rods of the retina that have a key role in the dim light vision. This membrane protein consists of an 11-cis-retinal chromophore bound to a seven transmembrane protein by means of a protonated Schiff base linkage. After illumination the retinal release from the receptor (and at the same time the decay of the active form, Meta II) result in a Trp fluorescence increase when measured by the fluorescence spectroscopy that differs in terms of half-life. Traditionally different in vivo and in vitro models, like mouse and bovine rhodopsin respectively, were thoroughly used to characterize it physiologically and biochemically. Keeping in mind that a large body of works about human genetic diseases related with opsins where studied on this models, the comparison with the human rhodopsin should be seriously taken into account. In this thesis bovine, murine and human rhodopsins were immunopurified and biochemically characterized and important biochemical differences in the retinal release rates were found, mainly between the diurnal (human and bovine) vs nocturnal (mouse) species. In addition, we also found a novel relevant amino acid position that appears to be significantly associated with rhodopsin molecular adaptation to the nocturnal (L290) and the diurnal (I290) niches throughout different terrestrial therian mammal species. We also demonstrate that L290I substitution increase the rate of retinal release, thus based on this results and previous studies we hypothesize that the important difference among diurnal vs nocturnal retinal release could be related to the variation into light intensity perception through species and an equilibrium between retina protection under intense light and dark adaption under dim-light.

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