Abstract
We report a structural characterization by electron microscopy and image analysis of a supramolecular complex consisting of photosystem I and light-harvesting complex I from the unicellular green alga Chlamydomonas reinhardtii. The complex is a monomer, has longest dimensions of 21.3 and 18.2 nm in projection, and is significantly larger than the corresponding complex in spinach. Comparison with photosystem I complexes from other organisms suggests that the complex contains about 14 light-harvesting proteins, two or three of which bind at the side of the PSI-H subunit. We suggest that special light-harvesting I proteins play a role in the binding of phosphorylated light-harvesting complex II in state 2.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Centrifugation, Density Gradient
-
Chlamydomonas reinhardtii / chemistry
-
Chlamydomonas reinhardtii / ultrastructure*
-
Cyanobacteria / chemistry
-
Cyanobacteria / ultrastructure
-
Electrophoresis, Polyacrylamide Gel
-
Image Processing, Computer-Assisted
-
Macromolecular Substances
-
Photosynthetic Reaction Center Complex Proteins / chemistry
-
Photosynthetic Reaction Center Complex Proteins / ultrastructure*
-
Photosystem I Protein Complex
-
Plant Proteins / chemistry
-
Spinacia oleracea / chemistry
-
Spinacia oleracea / ultrastructure
-
Thylakoids / chemistry
-
Thylakoids / ultrastructure
Substances
-
Macromolecular Substances
-
Photosynthetic Reaction Center Complex Proteins
-
Photosystem I Protein Complex
-
Plant Proteins