PROSITE documentation PDOC00786Photosystem I psaG and psaK proteins signature
Photosystem I (PSI) [1] is an integral membrane protein complex that uses light energy to mediate electron transfer from plastocyanin to ferredoxin. It is found in the chloroplasts of plants and cyanobacteria. PSI is composed of at least 14 different subunits, two of which - PSI-G (gene psaG) and PSI-K (gene psaK) - are small hydrophobic proteins of about 7 to 9 Kd and evolutionary related [2]. Both seem to contain two transmembrane regions. Cyanobacteria seem to encode only for PSI-K.
As a signature pattern, we selected the best conserved region which seems to correspond to the second transmembrane region.
Last update:December 2004 / Pattern and text revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Golbeck J.H. |
| Title | Structure, function and organization of the Photosystem I reaction center complex. | |
| Source | Biochim. Biophys. Acta 895:167-204(1987). | |
| PubMed ID | 3333014 |
| 2 | Authors | Kjaerulff S. Andersen B. Nielsen V.S. Moller B.L. Okkels J.S. |
| Title | The PSI-K subunit of photosystem I from barley (Hordeum vulgare L.). Evidence for a gene duplication of an ancestral PSI-G/K gene. | |
| Source | J. Biol. Chem. 268:18912-18916(1993). | |
| PubMed ID | 8360180 |
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