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Controlling electron transfer between the two cofactor chains of photosystem I by the redox state of one of their components

Santabarbara, S.; Bullock, B.; Rappaport, F.; Redding, K.; Biophys. J. 108, 1537-1547 (2015)

Data extracted from this reference:

Engineering
EC Number
Amino acid exchange
Commentary
Organism
1.97.1.12
F689N
site-directed mutagenesis of subunit PsaA, the mutation causes in an about 100fold decrease in the observed rate of cofactor phylloquinone PhQA- oxidation, resulting in a lifetime that exceeds that of the terminal electron donor, P700+. This situation allows a second photochemical charge separation event to be initiated before PhQA- has decayed, thereby mimicking in PSI a situation that occurs in type II reaction centers. Simulation of the pump-pump kinetics in PsaA-F689N, overview
Chlamydomonas reinhardtii
KM Value [mM]
EC Number
KM Value [mM]
KM Value Maximum [mM]
Substrate
Commentary
Organism
Structure
1.97.1.12
additional information
-
additional information
kinetics of electron transfer of wild-type and mutant enzymes, overview
Chlamydomonas reinhardtii
Localization
EC Number
Localization
Commentary
Organism
GeneOntology No.
Textmining
1.97.1.12
thylakoid
-
Chlamydomonas reinhardtii
9579
-
Natural Substrates/ Products (Substrates)
EC Number
Natural Substrates
Organism
Commentary (Nat. Sub.)
Natural Products
Commentary (Nat. Pro.)
Organism (Nat. Pro.)
Reversibility
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
Chlamydomonas reinhardtii
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
Chlamydomonas reinhardtii KRC91-1A
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
Organism
EC Number
Organism
Primary Accession No. (UniProt)
Commentary
Textmining
1.97.1.12
Chlamydomonas reinhardtii
P12154 AND P09144 AND Q00914
psaA, psaB, and psaC
-
1.97.1.12
Chlamydomonas reinhardtii KRC91-1A
P12154 AND P09144 AND Q00914
psaA, psaB, and psaC
-
Substrates and Products (Substrate)
EC Number
Substrates
Commentary Substrates
Literature (Substrates)
Organism
Products
Commentary (Products)
Literature (Products)
Organism (Products)
Reversibility
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744516
Chlamydomonas reinhardtii
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744516
Chlamydomonas reinhardtii KRC91-1A
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
Cofactor
EC Number
Cofactor
Commentary
Organism
Structure
1.97.1.12
phylloquinone
-
Chlamydomonas reinhardtii
Cofactor (protein specific)
EC Number
Cofactor
Commentary
Organism
Structure
1.97.1.12
phylloquinone
-
Chlamydomonas reinhardtii
Engineering (protein specific)
EC Number
Amino acid exchange
Commentary
Organism
1.97.1.12
F689N
site-directed mutagenesis of subunit PsaA, the mutation causes in an about 100fold decrease in the observed rate of cofactor phylloquinone PhQA- oxidation, resulting in a lifetime that exceeds that of the terminal electron donor, P700+. This situation allows a second photochemical charge separation event to be initiated before PhQA- has decayed, thereby mimicking in PSI a situation that occurs in type II reaction centers. Simulation of the pump-pump kinetics in PsaA-F689N, overview
Chlamydomonas reinhardtii
KM Value [mM] (protein specific)
EC Number
KM Value [mM]
KM Value Maximum [mM]
Substrate
Commentary
Organism
Structure
1.97.1.12
additional information
-
additional information
kinetics of electron transfer of wild-type and mutant enzymes, overview
Chlamydomonas reinhardtii
Localization (protein specific)
EC Number
Localization
Commentary
Organism
GeneOntology No.
Textmining
1.97.1.12
thylakoid
-
Chlamydomonas reinhardtii
9579
-
Natural Substrates/ Products (Substrates) (protein specific)
EC Number
Natural Substrates
Organism
Commentary (Nat. Sub.)
Natural Products
Commentary (Nat. Pro.)
Organism (Nat. Pro.)
Reversibility
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
Chlamydomonas reinhardtii
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
Chlamydomonas reinhardtii KRC91-1A
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
Substrates and Products (Substrate) (protein specific)
EC Number
Substrates
Commentary Substrates
Literature (Substrates)
Organism
Products
Commentary (Products)
Literature (Products)
Organism (Products)
Reversibility
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744516
Chlamydomonas reinhardtii
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744516
Chlamydomonas reinhardtii KRC91-1A
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
General Information
EC Number
General Information
Commentary
Organism
1.97.1.12
malfunction
site-directed mutagenesis of residues involved in the respective phylloquinone-binding sites results in a specific alteration of the rates of semiquinone oxidation. Mutation in the PhQA binding pocket (PsaA-F689N) in PSI of Chlamydomonas reinhardtii reduces down PhQA- oxidation kinetics by almost two orders of magnitude. This creates an unprecedented situation in which the reduction of P700+ is faster than the oxidation of the semiquinone, thereby providing the opportunity to initiate a second photochemical event while PhQA- is still present in ETCA, kinetics, overview
Chlamydomonas reinhardtii
1.97.1.12
physiological function
two functional electron transfer (ET) chains, related by a pseudo-C2 symmetry, are present in the reaction center of photosystem I (PSI). Due to slight differences in the environment around the cofactors of the two branches, there are differences in both the kinetics of ET and the proportion of ET that occurs on the two branches. The oxidation rates of the reduced phylloquinone (PhQ) cofactor differ by an order of magnitudes. The presence of PhQ-A does not impact the overall quantum yield and leads to an almost complete redistribution of the fractional utilization of the two functional ET chains, in favor of the one that does not bear the charged species, molecular mechanism that gives rise to the high quantum efficiency in PSI, overview
Chlamydomonas reinhardtii
General Information (protein specific)
EC Number
General Information
Commentary
Organism
1.97.1.12
malfunction
site-directed mutagenesis of residues involved in the respective phylloquinone-binding sites results in a specific alteration of the rates of semiquinone oxidation. Mutation in the PhQA binding pocket (PsaA-F689N) in PSI of Chlamydomonas reinhardtii reduces down PhQA- oxidation kinetics by almost two orders of magnitude. This creates an unprecedented situation in which the reduction of P700+ is faster than the oxidation of the semiquinone, thereby providing the opportunity to initiate a second photochemical event while PhQA- is still present in ETCA, kinetics, overview
Chlamydomonas reinhardtii
1.97.1.12
physiological function
two functional electron transfer (ET) chains, related by a pseudo-C2 symmetry, are present in the reaction center of photosystem I (PSI). Due to slight differences in the environment around the cofactors of the two branches, there are differences in both the kinetics of ET and the proportion of ET that occurs on the two branches. The oxidation rates of the reduced phylloquinone (PhQ) cofactor differ by an order of magnitudes. The presence of PhQ-A does not impact the overall quantum yield and leads to an almost complete redistribution of the fractional utilization of the two functional ET chains, in favor of the one that does not bear the charged species, molecular mechanism that gives rise to the high quantum efficiency in PSI, overview
Chlamydomonas reinhardtii