EC Number   |
Subunits |
Reference  |
|---|
    1.97.1.12 | More |
a cyanobacterial PSI monomer consists of 1112 protein subunits |
710876 |
| 1.97.1.12 | More |
plant and algal PSI complexes contain 14-15 protein subunits. Of these, only PsaA, PsaB, and PsaC bind the cofactors of the electron transfer system. PsaA and PsaB form the core complex around which other subunits are organized. The PsaC, PsaD, PsaH, and PsaE proteins form the stromal peripheral domain that contains the terminal electron donors and the ferredoxin-docking site. PsaN of plant and algal PSI is a lumenal peripheral protein. PsaN and the large lumenal domain of PsaF form the plastocyanin docking site of plant and algal PSI. The remaining proteins of PSI are integral membrane proteins with 13 transmembrane helices. The function of the PSI proteins |
710876 |
| 1.97.1.12 | More |
PsaE (a peripheral subunit of the PSI complex) is involved in the docking of ferredoxin/flavodoxin to the PSI complex and also participates in the cyclic electron transfer around phosphosystem I. The interactions formed between different subunits of the complex may be hydrophobic or electrostatic in nature |
711194 |
| 1.97.1.12 | More |
the PSI core complex prepared from cucumber cotyledons contains 80 chlorophylls per reaction center (P700) and eight polypeptides with apparent molecular masses of 65/63, 20,19.5,18.5,17.5,7.6, and 5.8 kDa. The amount of 18.5 kDa polypeptide in the PSI complex affects the activity. When this polypeptide is largely depleted, the complex is almost inactive. The inactivation is due to inhibition of electron transfer from plastocyanin to photooxidized P700. Chemical cross-linking and N-terminal amino acid sequencing experiments indicate that the 18.5-kDa polypeptide is the plastocyanin-docking protein and the psaF gene product |
712315 |
| 1.97.1.12 | More |
the photosystem I reaction center complex is composed of the 83 kDa subunits A and B, and at least six other subunits with molecular mass below 20 kDa |
712730 |
| 1.97.1.12 | More |
the photosystem I reaction center is obtained in two forms, monomeric and trimeric |
713434 |
| 1.97.1.12 | ? |
21000-22000 Da, photosystem 1 subunit PsaF that is involved in the docking of the electron-donor proteins plastocyanin and cytochrome c6, SDS-PAGE |
713465 |
| 1.97.1.12 | heterotetramer |
two-dimensional maps obtained by single particle electron microscopy clearly show that the tetramer lacks four-fold symmetry and is actually composed of a dimer of dimers with C2 symmetry, cryo-electron microscopy is used for 3D reconstruction of the PSI tetramer complex and a 3D model at 11.5 A resolution is obtained. A 2D map within the membrane plane of about 6.1 A is used for modeling, structure model comparison with the PSI structure of Thermosynechococcus elongatus at 2.5 A, PDB ID 1JB0, overview. The PsaL subunit of strain TS-821 is modeled using PsaL subunit of Pisum sativum as a template, PDB ID 4Y28L. The modeled PsaL subunit of TS-821 is used to substitute the existing PsaL subunit in crystal structure of Thermosynechococcus elongatus and most of the subunits from the crystal structure of Thermosynechococcus elongatus are fitted separately into the 3D volumemap of TS-821. Comparison of trimeric interface of Thermosynechococcus elongatus with interface type 1 of TS-821 |
744411 |
| 1.97.1.12 | More |
amino acid sequence comparisons |
744411 |
| 1.97.1.12 | trimer |
cyanobacterial PSI is usually trimeric |
744412 |
