Projection map of the reaction center-light harvesting 1 complex from Rhodopseudomonas viridis at 10Å resolution

The photosynthetic reaction center-light harvesting 1 complex from Rhodopseudomonas viridis was purified and reconstituted into two-dimensional crystals, The single-layered crystalline sheets with lattice parameters a=b=133.3 Angstrom and gamma=120 degrees were investigated by electron cryo-microscopy and the projection map at 10 Angstrom resolution was calculated, The opening diameter of the light-harvesting ring of 72 Angstrom is sufficient to allow slight movement of the reaction center within the ring, Based on characteristic features observed in the projection map, the mechanism of energy transfer from the light-harvesting 1 complex to the reaction center was discussed. (C) 1998 Federation of European Biochemical Societies.