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Rhodopsin-transducin heteropentamer: three-dimensional structure and biochemical characterization.

ABSTRACT: The process of vision is initiated when the G protein-coupled receptor, rhodopsin (Rho), absorbs a photon and transitions to its activated Rho(?) form. Rho(?) binds the heterotrimeric G protein, transducin (G(t)) inducing GDP to GTP exchange and G(t) dissociation. Using nucleotide depletion and affinity chromatography, we trapped and purified the resulting nucleotide-free Rho(?)·G(t) complex. Quantitative SDS-PAGE suggested a 2:1 molar ratio of Rho(?) to G(t) in the complex and its mass determined by scanning transmission electron microscopy was 221±12kDa. A 21.6Å structure was calculated from projections of negatively stained Rho(?)·G(t) complexes. The molecular envelope thus determined accommodated two Rho molecules together with one G(t) heterotrimer, corroborating the heteropentameric structure of the Rho(?)·G(t) complex.

SUBMITTER: Jastrzebska B

PROVIDER: S-EPMC3210324 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Rhodopsin-transducin heteropentamer: three-dimensional structure and biochemical characterization.

Jastrzebska Beata B Ringler Philippe P Lodowski David T DT Moiseenkova-Bell Vera V Golczak Marcin M Müller Shirley A SA Palczewski Krzysztof K Engel Andreas A

Journal of structural biology 20110906 3

The process of vision is initiated when the G protein-coupled receptor, rhodopsin (Rho), absorbs a photon and transitions to its activated Rho(∗) form. Rho(∗) binds the heterotrimeric G protein, transducin (G(t)) inducing GDP to GTP exchange and G(t) dissociation. Using nucleotide depletion and affinity chromatography, we trapped and purified the resulting nucleotide-free Rho(∗)·G(t) complex. Quantitative SDS-PAGE suggested a 2:1 molar ratio of Rho(∗) to G(t) in the complex and its mass determin ...[more]

PMID: 21925606

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