Abstract
N-(1-Anilinonaphthyl-4)maleimide (ANM) has been used to modify coupling factor 1 (CF1), the terminal coupling factor of photophosphorylation in chloroplasts. As with other monofunctional maleimides, incubation of thylakoids with ANM in the light, but not in the dark, causes energy transfer inhibition of photophosphorylation. In the dark, sites on both the gamma and epsilon subunits of CF1 are modified. The light-accessible site is also on the gamma subunit. Trypsin digestion of the enzyme after dithiothreitol activation reveals that the dark-and light-accessible sites on the gamma subunit are different amino acid residues. Fluorescence of ANM bound at the dark-and light-accessible sites has been measured after isolation of CF1 from thylakoids. The fluorescence emission maximum of ANM at the light-accessible site is blue-shifted and the quantum yield is increased 2-fold relative to ANM bound at dark-accessible sites. On the soluble enzyme, fluorescence polarization is high and equivalent for ANM bound at both dark-and light-accessible sites. Fluorescence energy transfer from a tryptophan in a hydrophilic region of the epsilon subunit to ANM bound to the epsilon subunit but not to the gamma subunit has been observed. The significance of these observations is discussed with respect to the structure of the gamma subunit and its role in conformational transitions within CF1 that occur during energization of the membrane.
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Claims 9
Claim · model-written summary
ANM incubation inhibited photophosphorylation energy transfer in light but not dark.
- Taxon
- spinach
Spinacia oleraceat0 - Treatment
- incubation of thylakoids with ANM in the lighte0
- Outcome
- energy transfer inhibition of photophosphorylatione0
- Direction
- inhibitione0
- Comparator
- in the darke0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“incubation of thylakoids with ANM in the light, but not in the dark, causes energy transfer inhibition of photophosphorylation”
Claim · model-written summary
In darkness, ANM modified sites on both gamma and epsilon CF1 subunits.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- In the darke0
- Gene
- CF1e0
- Outcome
- sites on both the gamma and epsilon subunits of CF1 are modifiede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“In the dark, sites on both the gamma and epsilon subunits of CF1 are modified.”
Claim · model-written summary
The light accessible ANM modification site was on the gamma subunit.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- light-accessible site is also on the gamma subunite0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“The light-accessible site is also on the gamma subunit.”
Claim · model-written summary
Dark and light accessible sites on the gamma subunit were different amino acid residues.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- dark-and light-accessible sites on the gamma subunit are different amino acid residuese0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“the dark-and light-accessible sites on the gamma subunit are different amino acid residues”
Claim · model-written summary
ANM at the light accessible site had a blue shifted fluorescence emission maximum relative to dark accessible sites.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- fluorescence emission maximum of ANMe0
- Direction
- blue-shiftede0
- Comparator
- ANM bound at dark-accessible sitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“The fluorescence emission maximum of ANM at the light-accessible site is blue-shifted and the quantum yield is increased 2-fold relative to ANM bound at dark-accessible sites.”
Claim · model-written summary
ANM at the light accessible site had a twofold greater quantum yield than ANM at dark accessible sites.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- quantum yielde0
- Direction
- increasede0
- Value
- 2-folde0
- Comparator
- ANM bound at dark-accessible sitese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“The fluorescence emission maximum of ANM at the light-accessible site is blue-shifted and the quantum yield is increased 2-fold relative to ANM bound at dark-accessible sites.”
Claim · model-written summary
On the soluble enzyme, fluorescence polarization was high and equivalent at dark and light accessible sites.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- fluorescence polarizatione0
- Direction
- equivalente0
- Qualifier
- On the soluble enzymee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“On the soluble enzyme, fluorescence polarization is high and equivalent for ANM bound at both dark-and light-accessible sites.”
Claim · model-written summary
Fluorescence energy transfer from epsilon subunit tryptophan to ANM was observed when ANM was bound to the epsilon subunit.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- Fluorescence energy transfer from a tryptophan in a hydrophilic region of the epsilon subunit to ANM bound to the epsilon subunite0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“Fluorescence energy transfer from a tryptophan in a hydrophilic region of the epsilon subunit to ANM bound to the epsilon subunit but not to the gamma subunit has been observed.”
Claim · model-written summary
Fluorescence energy transfer from epsilon subunit tryptophan to ANM was not observed when ANM was bound to the gamma subunit.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- not to the gamma subunite0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“spinach”
e0“Fluorescence energy transfer from a tryptophan in a hydrophilic region of the epsilon subunit to ANM bound to the epsilon subunit but not to the gamma subunit has been observed.”
The same questions in other papers
light · disease · Spinacia oleracea (spinach)Positive and negative results
2 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.