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The reaction centre of the photounit of Rhodospirillum rubrum is anchored to the light-harvesting complex with four-fold rotational disorder

Stahlberg, Henning ; Dubochet, Jacques ; Vogel, Horst ; Ghosh, Robin

In: Photosynthesis Research, 1998, vol. 55, no. 2-3, p. 363-368

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    Titre
    • The reaction centre of the photounit of Rhodospirillum rubrum is anchored to the light-harvesting complex with four-fold rotational disorder
    Auteur
    • Stahlberg, Henning. Laboratory for Ultrastructural Research (LAU), Biology Department, University of Lausanne (UNIL), CH-1015, Lausanne, Switzerland
    • Dubochet, Jacques. Laboratory for Ultrastructural Research (LAU), Biology Department, University of Lausanne (UNIL), CH-1015, Lausanne, Switzerland
    • Vogel, Horst. Laboratory of Physical Chemistry of Polymers and Membranes (LCPPM), Chemistry Department, Swiss Federal Institute of Technology (EPFL), CH-1015, Lausanne, Switzerland
    • Ghosh, Robin. Laboratory of Bioenergetics, University of Geneva, Ch. des Embouchis, CH-1254, Jussy-Lullier, Switzerland
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Photosynthesis Research, 1998, vol. 55, no. 2-3, p. 363-368. Kluwer Academic Publishers
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:322389
    Summary
    The minimal photounit of the photosynthetic membranes of the purple non-sulphur bacterium Rhodospirillum rubrum, comprising the reaction centre and the light-harvesting complex has been purified and crystallised in two dimensions in the presence of added phospholipids, and subsequently visualised by electron microscopy after negatively-staining. The position of the reaction centres within the light-harvesting ring has been determined at low resolution by the application of a new analysis for rotationally disordered identical units (here the reaction centres) within a two-dimensional crystalline lattice comprised of perfectly aligned unit cells (here the light-harvesting complexes). The reaction centre was found to preferentially occupy one of four orientations within the light-harvesting complex. The light-harvesting complex appears to be distorted to C4 symmetry, thus assuming a squarish shape when visualised by negative staining. A tentative structural model of the reaction centre-light-harvesting complex photounit which fits the experimental data is proposed