Abstract
We investigated the effects of elevated O2 pressure on the production of O 2 by photosynthetic organisms in several species of plants, algae, and a cyanobacterium. Using a noninvasive fluorometry technique to monitor sequential turnover of the photosystem II (PSII) reaction center as a function of O 2 pressures, we showed that none of the reactions of water oxidation are affected by elevated O 2 pressures up to 50-fold greater than atmospheric conditions. Thus, the terminal step of O 2 release from the water oxidation complex (S 4 → S 0 + O 2 + nH +) is not reversible in whole cells, leaves, or isolated thylakoid membranes containing PSII, in contrast to reports using detergent-extracted PSII complexes. This implies that there is no thermodynamically accessible intermediate that can be populated by preventing or reversing the O 2 release step with O 2 at atmospheric pressure. To assess the sensitivity of PSII charge recombination to O 2 pressure, we quantitatively modeled the consequences of two putative perturbations to the catalytic cycle of water oxidation within the framework of the Kok model. On the basis of the breadth of oxygenic phototrophs examined in this study, we conclude that O 2 accumulation in cells or the atmosphere does not suppress photosynthetic productivity through the reversal of water oxidation in contemporary phototrophs and would have been unlikely to influence the evolution of oxygenic photosynthesis.
| Original language | English |
|---|---|
| Pages (from-to) | 1381-1389 |
| Number of pages | 9 |
| Journal | Biochemistry |
| Volume | 48 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Feb 17 2009 |
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- Biochemistry
Cite this
Photosynthetic oxygen evolution is not reversed at high oxygen pressures : Mechanistic consequences for the water-oxidizing complex. / Kolling, Derrick R J; Brown, Tyler S.; Ananyev, Gennady; Dismukes, G Charles.
In: Biochemistry, Vol. 48, No. 6, 17.02.2009, p. 1381-1389.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Photosynthetic oxygen evolution is not reversed at high oxygen pressures
T2 - Mechanistic consequences for the water-oxidizing complex
AU - Kolling, Derrick R J
AU - Brown, Tyler S.
AU - Ananyev, Gennady
AU - Dismukes, G Charles
PY - 2009/2/17
Y1 - 2009/2/17
N2 - We investigated the effects of elevated O2 pressure on the production of O 2 by photosynthetic organisms in several species of plants, algae, and a cyanobacterium. Using a noninvasive fluorometry technique to monitor sequential turnover of the photosystem II (PSII) reaction center as a function of O 2 pressures, we showed that none of the reactions of water oxidation are affected by elevated O 2 pressures up to 50-fold greater than atmospheric conditions. Thus, the terminal step of O 2 release from the water oxidation complex (S 4 → S 0 + O 2 + nH +) is not reversible in whole cells, leaves, or isolated thylakoid membranes containing PSII, in contrast to reports using detergent-extracted PSII complexes. This implies that there is no thermodynamically accessible intermediate that can be populated by preventing or reversing the O 2 release step with O 2 at atmospheric pressure. To assess the sensitivity of PSII charge recombination to O 2 pressure, we quantitatively modeled the consequences of two putative perturbations to the catalytic cycle of water oxidation within the framework of the Kok model. On the basis of the breadth of oxygenic phototrophs examined in this study, we conclude that O 2 accumulation in cells or the atmosphere does not suppress photosynthetic productivity through the reversal of water oxidation in contemporary phototrophs and would have been unlikely to influence the evolution of oxygenic photosynthesis.
AB - We investigated the effects of elevated O2 pressure on the production of O 2 by photosynthetic organisms in several species of plants, algae, and a cyanobacterium. Using a noninvasive fluorometry technique to monitor sequential turnover of the photosystem II (PSII) reaction center as a function of O 2 pressures, we showed that none of the reactions of water oxidation are affected by elevated O 2 pressures up to 50-fold greater than atmospheric conditions. Thus, the terminal step of O 2 release from the water oxidation complex (S 4 → S 0 + O 2 + nH +) is not reversible in whole cells, leaves, or isolated thylakoid membranes containing PSII, in contrast to reports using detergent-extracted PSII complexes. This implies that there is no thermodynamically accessible intermediate that can be populated by preventing or reversing the O 2 release step with O 2 at atmospheric pressure. To assess the sensitivity of PSII charge recombination to O 2 pressure, we quantitatively modeled the consequences of two putative perturbations to the catalytic cycle of water oxidation within the framework of the Kok model. On the basis of the breadth of oxygenic phototrophs examined in this study, we conclude that O 2 accumulation in cells or the atmosphere does not suppress photosynthetic productivity through the reversal of water oxidation in contemporary phototrophs and would have been unlikely to influence the evolution of oxygenic photosynthesis.
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UR - http://www.scopus.com/inward/citedby.url?scp=64349104744&partnerID=8YFLogxK
U2 - 10.1021/bi801774f
DO - 10.1021/bi801774f
M3 - Article
C2 - 19166323
AN - SCOPUS:64349104744
VL - 48
SP - 1381
EP - 1389
JO - Biochemistry
JF - Biochemistry
SN - 0006-2960
IS - 6
ER -