Abstract
The 4 Å X-ray structure model of trimeric photosystem I of the cyanobacterium Synechococcus elongatus reveals 31 transmembrane, nine surface and three stromal α-helices per monomer, assigned to the 11 protein subunits: PsaA and PsaB are related by a pseudo two-fold axis normal to the membrane plane, along which the electron transfer pigments are arranged. 65 antenna chlorophyll a (Chl a) molecules separated by ≤16 Å form an oval, clustered net, continuous with the electron transfer chain through the second and third Chl a pairs of the electron transfer system. This suggests a dual role for these Chl a both in excitation energy and electron transfer. The architecture of the protein core indicates quinone and iron-sulphur type reaction centres to have a common ancestor.
Original language | English (US) |
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Pages (from-to) | 965-973 |
Number of pages | 9 |
Journal | Nature Structural Biology |
Volume | 3 |
Issue number | 11 |
DOIs | |
State | Published - Nov 1 1996 |
Externally published | Yes |
ASJC Scopus subject areas
- Structural Biology
- Biochemistry
- Genetics