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Coupling Efficiency of Rhodopsin and Transducin in the Bicelle Mixtures
Author(s) -
Kaya Ali Ilkay,
Thaker Tarjani M,
Meier Scott M,
Preininger Anita M,
Iverson Tina M,
Hamm Heidi E
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.769.7
Subject(s) - rhodopsin , transducin , chemistry , g protein coupled receptor , biophysics , gtp' , crystallography , biochemistry , receptor , biology , retinal , enzyme
Although crystal structures of several GPCRs (Rhodopsin, β 1 ‐AR, β 2 ‐AR, α 2 A‐AR) and G proteins (G t and G i ) have been determined, the exact molecular mechanism of receptor mediated G protein activation is not fully understood. We are studying the biochemical and structural characteristics of rhodopsin in bicelles (in complex with G t protein) in order to better understand the mechanism leading to receptor mediated nucleotide release. This study compares the efficiency of various bicelle preparations in stabilizing rhodopsin structure in the absence and presence of G proteins using fluorescence and crystallographic approaches. Our results demonstrate that the extra metarhodopsin II stability increases when soluble rhodopsin is mixed with bicelles. Additionally, the kinetics of extra metarhodopsin II decay of rhodopsin in the bicelle environment is presented, along with receptor mediated G protein activation as measured by GTP γ S binding. These data suggest that a membrane‐like structure is required for formation of a stable complex between rhodopsin and G protein, and further, that bicelles provide a native‐like environment for soluble rhodopsin. This may facilitate crystallization trails of the rhodopsin‐G protein complex.