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Literature summary for 1.97.1.12 extracted from
- Mutations in algal and cyanobacterial photosystem I that independently affect the yield of initial charge separation in the two electron transfer cofactor branches (2018), Biochim. Biophys. Acta, 1859, 42-55 .
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| N591L | site-directed mutagenesis of psaB, the mutant shows structural differences and altered activity compared to the wild-type enzyme, detailed overview | Synechocystis sp. PCC 6803 |
| N591L | site-directed mutagenesis of psaB, the mutant shows structural differences and altered activity compared to the wild-type enzyme, detailed overview | Chlamydomonas reinhardtii |
| N604L | site-directed mutagenesis of psaA, the mutant shows structural differences and altered activity compared to the wild-type enzyme, detailed overview | Synechocystis sp. PCC 6803 |
| N604L | site-directed mutagenesis of psaA, the mutant shows structural differences and altered activity compared to the wild-type enzyme, detailed overview | Chlamydomonas reinhardtii |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| thylakoid | - |
Synechocystis sp. PCC 6803 | 9579 | - |
| thylakoid | - |
Chlamydomonas reinhardtii | 9579 | - |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| reduced plastocyanin + oxidized ferredoxin + hv | Synechocystis sp. PCC 6803 | - |
oxidized plastocyanin + reduced ferredoxin | - |
? |  |
| reduced plastocyanin + oxidized ferredoxin + hv | Chlamydomonas reinhardtii | - |
oxidized plastocyanin + reduced ferredoxin | - |
? | |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Chlamydomonas reinhardtii | P12154 AND P09144 AND Q00914 | psaA, psaB, and psaC | - |
| Synechocystis sp. PCC 6803 | P29254 AND P29255 AND P32422 | psaA, psaB, and psaC | - |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| recombinant His6-tagged enzyme from thylakoid membranes by nickel affinity chromatography and ultrafiltration | Chlamydomonas reinhardtii |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| additional information | photo-oxidation of P700 causes a broad increase in absorption in the near-infrared region due to presence of a chlorophyll cation radical (P700+) | Synechocystis sp. PCC 6803 | ? | - |
? | |
| additional information | photo-oxidation of P700 causes a broad increase in absorption in the near-infrared region due to presence of a chlorophyll cation radical (P700+) | Chlamydomonas reinhardtii | ? | - |
? | |
| reduced plastocyanin + oxidized ferredoxin + hv | - |
Synechocystis sp. PCC 6803 | oxidized plastocyanin + reduced ferredoxin | - |
? | |
| reduced plastocyanin + oxidized ferredoxin + hv | - |
Chlamydomonas reinhardtii | oxidized plastocyanin + reduced ferredoxin | - |
? | |
Subunits
| Subunits | Comment | Organism |
|---|---|---|
| trimer | cyanobacterial PSI is usually trimeric | Synechocystis sp. PCC 6803 |
| trimer | cyanobacterial PSI is usually trimeric | Chlamydomonas reinhardtii |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| PSI | - |
Synechocystis sp. PCC 6803 |
| PSI | - |
Chlamydomonas reinhardtii |
Temperature Optimum [°C]
| Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
|---|---|---|---|
| 22 | - |
assay at room temperature | Synechocystis sp. PCC 6803 |
| 22 | - |
assay at room temperature | Chlamydomonas reinhardtii |
pH Optimum
| pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
|---|---|---|---|
| 7.5 | - |
assay at | Synechocystis sp. PCC 6803 |
| 7.5 | - |
assay at | Chlamydomonas reinhardtii |
Cofactor
| Cofactor | Comment | Organism | Structure |
|---|---|---|---|
| additional information | the electron-transfer cofactors are arranged in two nearly symmetric branches extending across the membrane from P700, which is a dimer of Chl a and a C-13 epimer of Chl a. Each branch contains an additional pair of Chl a molecules (ec2A/ec3A or ec2B/ec3B) and a phylloquinone (PhQA or PhQB), overview | Synechocystis sp. PCC 6803 | |
| additional information | the electron-transfer cofactors are arranged in two nearly symmetric branches extending across the membrane from P700, which is a dimer of Chl a and a C-13 epimer of Chl a. Each branch contains an additional pair of Chl a molecules (ec2A/ec3A or ec2B/ec3B) and a phylloquinone (PhQA or PhQB), overview | Chlamydomonas reinhardtii | |
| phylloquinone | - |
Synechocystis sp. PCC 6803 | |
| phylloquinone | - |
Chlamydomonas reinhardtii | |
General Information
| General Information | Comment | Organism |
|---|---|---|
| malfunction | the PsaA-N604L mutation (near ec2B) results in a 50% reduction in the amount of electron transfer in the cofactor B-branch, while the PsaB-N591L mutation (near ec2A) results in a 70% reduction in the amount of electron transfer in the cofactor A-branch. The PsaB-N591L mutation had a significant effect upon trapping, while the PsaA-N604L mutation does not have a significant effect upon trapping | Synechocystis sp. PCC 6803 |
| malfunction | the PsaA-N604L mutation (near ec2B) results in a 50% reduction in the amount of electron transfer in the cofactor B-branch, while the PsaB-N591L mutation (near ec2A) results in a 70% reduction in the amount of electron transfer in the cofactor A-branch. The PsaB-N591L mutation had a significant effect upon trapping, while the PsaA-N604L mutation does not have a significant effect upon trapping | Chlamydomonas reinhardtii |
| additional information | in photosystem I, light-induced electron transfer can occur in either of two symmetry-related branches of cofactors, each of which is composed of a pair of chlorophylls (ec2A/ec3A or ec2B/ec3B) and a phylloquinone (PhQA or PhQB). The axial ligand to the central Mg2+ of the ec2A and ec2B chlorophylls is a water molecule that is also H-bonded to a nearby Asn residue, an important interaction for charge separation by converting each of the Asn residues to a Leu in the cyanobacterium Synechocystis sp. PCC6803. Each branch of the reaction center appears to operate independently of the other in carrying out light-induced charge separation | Synechocystis sp. PCC 6803 |
| additional information | in photosystem I, light-induced electron transfer can occur in either of two symmetry-related branches of cofactors, each of which is composed of a pair of chlorophylls (ec2A/ec3A or ec2B/ec3B) and a phylloquinone (PhQA or PhQB). The axial ligand to the central Mg2+ of the ec2A and ec2B chlorophylls is a water molecule that is also H-bonded to a nearby Asn residue, an important interaction for charge separation by converting each of the Asn residues to a Leu in the green alga, Chlamydomonas reinhardtii. Each branch of the reaction center appears to operate independently of the other in carrying out light-induced charge separation | Chlamydomonas reinhardtii |
| physiological function | photosystem I (PSI) is a large pigment-protein complex that functions as a light-driven oxidoreductase, catalyzing an otherwise uphill electron transfer from cytochrome c or plastocyanin to ferredoxin or flavodoxin | Synechocystis sp. PCC 6803 |
| physiological function | photosystem I (PSI) is a large pigment-protein complex that functions as a light-driven oxidoreductase, catalyzing an otherwise uphill electron transfer from cytochrome c or plastocyanin to ferredoxin or flavodoxin | Chlamydomonas reinhardtii |
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