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Redox regulation of the antimycin A sensitive pathway of cyclic electron flow around photosystem I in higher plant thylakoids

Strand, D.; Fisher, N.; Davis, G.; Kramer, D.; Biochim. Biophys. Acta 1857, 1-6 (2016)
No PubMed abstract available

Data extracted from this reference:

Activating Compound
EC Number
Activating Compound
Commentary
Organism
Structure
1.97.1.12
additional information
isolation of thylakoids while in the continuous presence of reduced thiol reductant dithiothreitol (DTT), but not oxidized DTT, maintains high cyclic electron flow of photosystem I activity through an antimycin A-sensitive ferredoxin:quinone reductase (FQR). FQR mediated cyclic electron flow is highly sensitive to thylakoid isolation conditions, overview
Spinacia oleracea
1.97.1.12
reduced DTT
does not reduce the plastoquinone pool directly, but is dependent on ferredoxin, consistent with the involvement of a ferredoxin-dependent reaction, most likely the ferredoxin:quinone reductase (FQR)
Spinacia oleracea
Localization
EC Number
Localization
Commentary
Organism
GeneOntology No.
Textmining
1.97.1.12
chloroplast
-
Spinacia oleracea
9507
-
1.97.1.12
thylakoid
-
Spinacia oleracea
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
Spinacia oleracea
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
Organism
EC Number
Organism
Primary Accession No. (UniProt)
Commentary
Textmining
1.97.1.12
Spinacia oleracea
P80470 AND P06512 AND P10098
psaA, psaB, and psaC
-
Source Tissue
EC Number
Source Tissue
Commentary
Organism
Textmining
1.97.1.12
leaf
-
Spinacia oleracea
-
Substrates and Products (Substrate)
EC Number
Substrates
Commentary Substrates
Literature (Substrates)
Organism
Products
Commentary (Products)
Literature (Products)
Organism (Products)
Reversibility
1.97.1.12
additional information
thylakoids freshly isolated from spinach are assayed for their ability to generate a light driven proton gradient. While high rates of cyclic electron flow are observed in vivo, isolated thylakoids show only very slow rates, suggesting that the activity of a key complex is lost or downregulated upon isolation. Isolation of thylakoids in the complete absence of DTTRED leads to loss of CEF activity that is only partially restored by subsequent addition of 2 mM DTTRED, redox titration of CEF activity, overview
744410
Spinacia oleracea
?
-
-
-
-
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744410
Spinacia oleracea
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
pH Optimum
EC Number
pH Optimum Minimum
pH Optimum Maximum
Commentary
Organism
1.97.1.12
7.6
-
assay at
Spinacia oleracea
Cofactor
EC Number
Cofactor
Commentary
Organism
Structure
1.97.1.12
Ferredoxin
-
Spinacia oleracea
Activating Compound (protein specific)
EC Number
Activating Compound
Commentary
Organism
Structure
1.97.1.12
additional information
isolation of thylakoids while in the continuous presence of reduced thiol reductant dithiothreitol (DTT), but not oxidized DTT, maintains high cyclic electron flow of photosystem I activity through an antimycin A-sensitive ferredoxin:quinone reductase (FQR). FQR mediated cyclic electron flow is highly sensitive to thylakoid isolation conditions, overview
Spinacia oleracea
1.97.1.12
reduced DTT
does not reduce the plastoquinone pool directly, but is dependent on ferredoxin, consistent with the involvement of a ferredoxin-dependent reaction, most likely the ferredoxin:quinone reductase (FQR)
Spinacia oleracea
Cofactor (protein specific)
EC Number
Cofactor
Commentary
Organism
Structure
1.97.1.12
Ferredoxin
-
Spinacia oleracea
Localization (protein specific)
EC Number
Localization
Commentary
Organism
GeneOntology No.
Textmining
1.97.1.12
chloroplast
-
Spinacia oleracea
9507
-
1.97.1.12
thylakoid
-
Spinacia oleracea
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
Spinacia oleracea
-
oxidized plastocyanin + reduced ferredoxin
-
-
?
Source Tissue (protein specific)
EC Number
Source Tissue
Commentary
Organism
Textmining
1.97.1.12
leaf
-
Spinacia oleracea
-
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
additional information
thylakoids freshly isolated from spinach are assayed for their ability to generate a light driven proton gradient. While high rates of cyclic electron flow are observed in vivo, isolated thylakoids show only very slow rates, suggesting that the activity of a key complex is lost or downregulated upon isolation. Isolation of thylakoids in the complete absence of DTTRED leads to loss of CEF activity that is only partially restored by subsequent addition of 2 mM DTTRED, redox titration of CEF activity, overview
744410
Spinacia oleracea
?
-
-
-
-
1.97.1.12
reduced plastocyanin + oxidized ferredoxin + hv
-
744410
Spinacia oleracea
oxidized plastocyanin + reduced ferredoxin
-
-
-
?
pH Optimum (protein specific)
EC Number
pH Optimum Minimum
pH Optimum Maximum
Commentary
Organism
1.97.1.12
7.6
-
assay at
Spinacia oleracea
General Information
EC Number
General Information
Commentary
Organism
1.97.1.12
physiological function
the chloroplast must regulate supply of reducing equivalents and ATP to meet rapid changes in downstream metabolic demands. Cyclic electron flow around photosystem I (CEF) is proposed to balance the ATP/NADPH budget by using reducing equivalents to drive plastoquinone reduction, leading to the generation of proton motive force and subsequent ATP synthesis. Photosynthetic energy is stored by linear electron flow (LEF), which involves electron transfer through both photosystem II (PS II) and photosystem I (PS I). Multiple alternative electron pathways are identified or proposed including the water-water cycle, themalate shunt, the plastid terminal oxidase, and cyclic electron flow around photosystem I (CEF). Cyclic electron flow can alleviate an ATP deficit by passing electrons fromthe acceptor side of PS I back to PQ, driving the translocation of protons into the lumen without net reduction of NADP+. High rates of CEF are readily measured in vivo
Spinacia oleracea
General Information (protein specific)
EC Number
General Information
Commentary
Organism
1.97.1.12
physiological function
the chloroplast must regulate supply of reducing equivalents and ATP to meet rapid changes in downstream metabolic demands. Cyclic electron flow around photosystem I (CEF) is proposed to balance the ATP/NADPH budget by using reducing equivalents to drive plastoquinone reduction, leading to the generation of proton motive force and subsequent ATP synthesis. Photosynthetic energy is stored by linear electron flow (LEF), which involves electron transfer through both photosystem II (PS II) and photosystem I (PS I). Multiple alternative electron pathways are identified or proposed including the water-water cycle, themalate shunt, the plastid terminal oxidase, and cyclic electron flow around photosystem I (CEF). Cyclic electron flow can alleviate an ATP deficit by passing electrons fromthe acceptor side of PS I back to PQ, driving the translocation of protons into the lumen without net reduction of NADP+. High rates of CEF are readily measured in vivo
Spinacia oleracea