title: Docosahexaenoic acid phospholipid differentially modulates the conformation of G90V and N55K rhodopsin mutants associated with retinitis pigmentosa.
abstract: Rhodopsin is the visual photoreceptor of the retinal rod cells that mediates dim light vision and a prototypical member of the G protein-coupled receptor superfamily. The structural stability and functional performance of rhodopsin are modulated by membrane lipids. Docosahexaenoic acid has been shown to interact with native rhodopsin but no direct evidence has been established on the effect of such lipid on the stability and regeneration of rhodopsin mutants associated with retinal diseases. The stability and regeneration of two thermosensitive mutants G90V and N55K, associated with the retinal degenerative disease retinitis pigmentosa, have been analyzed in docosohexaenoic phospholipid (1,2-didocosa-hexaenoyl-sn-glycero-3-phosphocholine; DDHA-PC) liposomes. G90V mutant reconstituted in DDHA-PC liposomes significantly increased its thermal stability, but N55K mutant showed similar thermal sensitivity both in dodecyl maltoside detergent solution and in DDHA-PC liposomes. The retinal release process, measured by fluorescence spectroscopy, became faster in the lipid system for the two mutants. The opsin conformation was stabilized for the G90V mutant allowing improved retinal uptake whereas no chromophore binding could be detected for N55K opsin after photoactivation. The results emphasize the distinct role of DHA on different phenotypic rhodopsin mutations associated with classical (G90V) and sector (N55K) retinitis pigmentosa.
authors.affiliation: Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Dong
authors.affiliation: Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain.
authors.forename: María Guadalupe
authors.initials: MG
authors.lastname: Herrera-Hernández
authors.affiliation: Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Ramon
authors.affiliation: Grup de Biotecnologia Molecular i Industrial, Centre de Biotecnologia Molecular, Departament d'Enginyeria Química, Universitat Politècnica de Catalunya, Edifici Gaia, Rambla de Sant Nebridi 22, 08222 Terrassa, Catalonia, Spain. Electronic address: pere.garriga@upc.edu.
authors.forename: Pere
authors.initials: P
authors.lastname: Garriga
mesh_terms: D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004281:Docosahexaenoic Acids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D009154:Mutation; D010767:Phosphorylcholine / Q000737:chemistry*; D011487:Protein Conformation; D055550:Protein Stability; D012174:Retinitis Pigmentosa / Q000209:etiology*; D012243:Rhodopsin / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D008081:Liposomes; D010767:Phosphorylcholine; D004281:Docosahexaenoic Acids; D012243:Rhodopsin
keywords: Artificial membranes; Lipid-protein interactions; Receptor stability; Retinal degeneration; Rhodopsin