Light-harvesting chlorophyll a/b-protein: Three-dimensional structure of a reconstituted membrane lattice in negative stain.
The three-dimensional structure of a negatively stained hexagonal membrane lattice containing the light-harvesting chlorophyll a/b-protein complex and phospholipids has been determined to 30-A resolution by image reconstruction from electron micrographs. This lattice has p321 symmetry, a lattice constant of 125 A and a thickness of 75 A. The monomer is shown to be an elongated molecule about 65 A long in the dimension perpendicular to the plane of the membrane. It spans the hydrophobic domain of the membrane in an asymmetric fashion, projecting [unk]20 A from one surface and less from the other. On the basis of this image and available biochemical data, the structure of the complex in the native thylakoid membrane is proposed.
Department of Biochemistry, Columbia University, New York, NY 10032.
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