Two-dimensional crystallization of the light-harvesting complex from Rhodospirillum rubrum.
Homogeneous detergent-solubilized B873 light-harvesting complexes from a carotenoid-less mutant of the purple non-sulfur bacterium, Rhodospirillum rubrum G9, were reassembled spontaneously into two-dimensional (2D) hexagonal arrays during extensive and controlled dialysis. As the complexes contain only 1 to 2 mol phospholipid per mol alpha beta dimer, the arrays formed by a self assembly process are primary due to protein-protein interactions. The hexagonal lattices were analyzed by negative stain electron microscopy and digital image processing. They exhibited a unit cell size of 12.3 nm, in close agreement with the particle diameter of the active photo-unit in native chromatophore membranes. The unit cell contains a central 5 nm stain-filled depression, embraced by a ring with an outer diameter of 10 nm.
Department of Microbiology, University of Basel, Switzerland.
R
R
Ghosh
A
A
Hoenger
A
A
Hardmeyer
D
D
Mihailescu
R
R
Bachofen
A
A
Engel
J P
JP
Rosenbusch
D003460:Crystallization; D007089:Image Enhancement; D008854:Microscopy, Electron; D016624:Negative Staining; D045322:Photosynthetic Reaction Center Complex Proteins / Q000648:ultrastructure*; D012246:Rhodospirillum / Q000648:ultrastructure*
D045322:Photosynthetic Reaction Center Complex Proteins