Rhodopsin is the visual pigment that mediates dim-light vision in vertebrates and is a model system for the study of retinal disease. The majority of rhodopsin experiments are performed using bovine rhodopsin; however, recent evidence suggests that significant functional differences exist among mammalian rhodopsins. In this study, we identify differences in both thermal decay and light-activated retinal release rates between bovine and human rhodopsin and perform mutagenesis studies to highlight two clusters of substitutions that contribute to these differences. We also demonstrate that the retinitis pigmentosa-associated mutation G51A behaves differently in human rhodopsin compared to bovine rhodopsin and determine that the thermal decay rate of an ancestrally reconstructed mammalian rhodopsin displays an intermediate phenotype compared to the two extant pigments.
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http://dx.doi.org/10.1002/1873-3468.12637 | DOI Listing |
Biochemistry
December 2024
Gavin Herbert Eye Institute - Center for Translational Vision Research, Department of Ophthalmology, University of California, Irvine, Irvine, California 92697, United States.
Arrestins halt signal transduction by binding to the phosphorylated C-termini of activated G protein-coupled receptors. Arrestin-1, the first subtype discovered, binds to rhodopsin in rod cells. Mutations in , the gene encoding Arrestin-1, are linked to Oguchi disease, characterized by delayed dark adaptation.
View Article and Find Full Text PDFProtein Expr Purif
March 2025
Centre des Sciences Du Goût et de l'Alimentation, CNRS, INRAE, Institut Agro, Université de Bourgogne, F-21000, France. Electronic address:
Bitter is one of the five basic taste qualities, along with salty, sour, sweet and umami, used by mammals to access the quality of their food and orient their eating behaviour. Bitter taste detection prevents the ingestion of food potentially contaminated by bitter-tasting toxins. Bitter taste perception is mediated by a family of G protein-coupled receptors (GPCRs) called TAS2Rs.
View Article and Find Full Text PDFJ Phys Chem B
December 2024
Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1/3, Moscow 119991, Russia.
The primary photoisomerization reactions of the all- to 13- and 11- to all- retinal protonated Schiff base (RPSB) in microbial and animal rhodopsins, respectively, occur on a subpicosecond time scale with high quantum yields. At the same time, the isolated RPSB exhibits slower excited-state decay, in particular, in its all- form, and hence the interaction with the protein environment is capable of changing the time scale as well as the specificity of the reaction. Here, by using the high-level QM/MM calculations, we provide a comparative study of the primary photoresponse of and RPSB isomers in both the initial forms and first photoproducts of microbial rhodopsin 2 (KR2) and bacteriorhodopsin (BR), and animal visual rhodopsin (Rho).
View Article and Find Full Text PDFBiochem Cell Biol
October 2024
Department of Chemistry and Biomolecular Sciences, University of Ottawa, 150 Louis-Pasteur Pvt, Ottawa, ON K1N 6N5, Canada.
Ste2 and Ste3 are G-protein-coupled receptors (GPCRs) shown to play roles in hyphal chemotropism and fungal plant pathogenesis in response to activity arising from host-secreted peroxidases. Here, we follow up on the observation that chemotropism is dependent on both Ste2 and Ste3 being present; testing the possibility that this might be due to formation of an Ste2-Ste3 heterodimer. Bioluminescence resonance energy transfer (BRET) analyses were conducted in , where the addition of horse radish peroxidase (HRP) was found to increase the transfer of energy from the inducibly expressed Ste3-Nano luciferase donor, to the constitutively expressed Ste2-yellow fluorescent protein (YFP) acceptor, compared to controls.
View Article and Find Full Text PDFbioRxiv
September 2024
Institute for Modeling Collaboration and Innovation, University of Idaho, Moscow, Idaho, United States of America.
Visual pigments are essential for converting light into electrical signals during vision. Composed of an opsin protein and a retinal-based chromophore, pigments in vertebrate rods (Rh1) and cones (Rh2) have different spectral sensitivities, with distinct peak absorption wavelengths determined by the shape and composition of the chromophore binding pocket. Despite advances in understanding Rh1 pigments such as bovine rhodopsin, the molecular basis of spectral shifts in Rh2 cone opsins has been less studied, particularly the E122Q mutation, which accounts for about half of the observed spectral shift in these pigments.
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