KM Value [mM] | KM Value Maximum [mM] | Substrate | Comment | Organism | Structure |
---|---|---|---|---|---|
additional information | - |
additional information | Michaelis-Menten kinetics, three-state electron transport recombinantion kinetics, and kinetic modeling, interaction of PS I with external acceptors, methylviologen, and oxygen, detailed overview | Synechocystis sp. PCC 6803 |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
thylakoid membrane | - |
Synechocystis sp. PCC 6803 | 42651 | - |
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 | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Synechocystis sp. PCC 6803 | P29254 AND P29255 AND P32422 | psaA, psaB, and psaC | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | upon light excitation, the excited singlet state of the primary electron donor, P700 delivers an electron to the primary Chl acceptor A0A/ A0B forming the charge-separated state P700 +A0-. The electron is then transferred in sequence to A1A/ A1B, to the iron-sulfur cluster FX, and ultimately to FA/FB. The side production of superoxide radical in the A1-site by oxygen reduction via the Mehler reaction might comprise about 0.3% of the total electron flow in photosystem I, PS I. Interaction of PS I with external acceptors, methylviologen, 2,3-dichloro-naphthoquinone and oxygen, overview. Analysis of PS I complexes containing various quinones in the A1-binding site, i.e. phylloquinone PhQ, plastoquinone-9 PQ and 2,3-dichloro-naphthoquinone, as well as FX-core complexes, depleted of terminal iron-sulfur FA/FB clusters | Synechocystis sp. PCC 6803 | ? | - |
? | |
reduced plastocyanin + oxidized ferredoxin + hv | - |
Synechocystis sp. PCC 6803 | oxidized plastocyanin + reduced ferredoxin | - |
? |
Subunits | Comment | Organism |
---|---|---|
More | the membrane-embedded core of each PS I monomer is formed by the two largest subunits, PsaA and PsaB, which bind electron transport cofactors arranged in two symmetrical branches, A and B, extending from P700, a pair of chlorophyll a molecules located on the lumenal side, to the [4Fe-4S] cluster FX, placed on the opposite stromal side of the complex | Synechocystis sp. PCC 6803 |
Synonyms | Comment | Organism |
---|---|---|
PS I | - |
Synechocystis sp. PCC 6803 |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
phylloquinone | - |
Synechocystis sp. PCC 6803 | |
plastoquinone | - |
Synechocystis sp. PCC 6803 | |
[4Fe-4S]-center | cluster Fx | Synechocystis sp. PCC 6803 |
General Information | Comment | Organism |
---|---|---|
additional information | the membrane-embedded core of each PS I monomer is formed by the two largest subunits, PsaA and PsaB, which bind electron transport cofactors arranged in two symmetrical branches, A and B, extending from P700, a pair of chlorophyll a molecules located on the lumenal side, to the [4Fe-4S] cluster FX, placed on the opposite stromal side of the complex. Each of the two branches, related by a pseudo-C2 rotation axis which passes through P700 and FX, carries two electronically coupled Chl a molecules (termed A0A or A0B) and one phylloquinone A1A or A1B | Synechocystis sp. PCC 6803 |
physiological function | photosystem I (PS I) is a key pigment-protein complex of the electron transfer (ET) chain of oxygenic photosynthetic organisms. It includes both a large antenna system for harvesting solar energy and a photochemical reaction center catalyzing charge separation across the membrane. PS I is the key element of the energy-transducing pathways because the electron flow in thylakoids is controlled by the redox states of cofactors in the acceptor part of PS I | Synechocystis sp. PCC 6803 |