Abstract
When organisms that perform oxygenic photosynthesis are exposed to strong visible or UV light, inactivation of photosystem II (PSII) occurs. However, such organisms are able rapidly to repair the photoinactivated PSII. The phenomenon of photoinactivation and repair is known as photoinhibition. Under normal laboratory conditions, the rate of repair is similar to or faster than the rate of photoinactivation, preventing the detailed analysis of photoinactivation and repair as separate processes. We report here that, using strong UV-A light from a laser, we were able to analyze separately the photoinactivation and repair of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803. Very strong UV-A light at 364 nm and a photon flux density of 2600 μmol photons m -2 s-1 inactivated the oxygen-evolving machinery and the photochemical reaction center of PSII within 1 or 2 min before the first step in the repair process, namely, the degradation of the D1 protein, occurred. During subsequent incubation of cells in weak visible light, the activity of PSII recovered fully within 30 min and this process depended on protein synthesis. During subsequent incubation of cells in darkness for 60 min, the D1 protein of the photoinactivated PSII was degraded. Further incubation in weak visible light resulted in the rapid restoration of the activity of PSII. These observations suggest that very strong UV-A light is a useful tool for the analysis of the repair of PSII after photoinactivation.
| Original language | English |
|---|---|
| Pages (from-to) | 123-129 |
| Number of pages | 7 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1757 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Feb 1 2006 |
| Externally published | Yes |
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Keywords
- D1 protein
- Photoinhibition
- Photosystem II
- Synechocystis
- UV-A light
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Cell Biology
Cite this
Very strong UV-A light temporally separates the photoinhibition of photosystem II into light-induced inactivation and repair. / Zsiros, Otto; Allakhverdiev, Suleyman; Higashi, Shoichi; Watanabe, Masakatsu; Nishiyama, Yoshitaka; Murata, Norio.
In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1757, No. 2, 01.02.2006, p. 123-129.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Very strong UV-A light temporally separates the photoinhibition of photosystem II into light-induced inactivation and repair
AU - Zsiros, Otto
AU - Allakhverdiev, Suleyman
AU - Higashi, Shoichi
AU - Watanabe, Masakatsu
AU - Nishiyama, Yoshitaka
AU - Murata, Norio
PY - 2006/2/1
Y1 - 2006/2/1
N2 - When organisms that perform oxygenic photosynthesis are exposed to strong visible or UV light, inactivation of photosystem II (PSII) occurs. However, such organisms are able rapidly to repair the photoinactivated PSII. The phenomenon of photoinactivation and repair is known as photoinhibition. Under normal laboratory conditions, the rate of repair is similar to or faster than the rate of photoinactivation, preventing the detailed analysis of photoinactivation and repair as separate processes. We report here that, using strong UV-A light from a laser, we were able to analyze separately the photoinactivation and repair of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803. Very strong UV-A light at 364 nm and a photon flux density of 2600 μmol photons m -2 s-1 inactivated the oxygen-evolving machinery and the photochemical reaction center of PSII within 1 or 2 min before the first step in the repair process, namely, the degradation of the D1 protein, occurred. During subsequent incubation of cells in weak visible light, the activity of PSII recovered fully within 30 min and this process depended on protein synthesis. During subsequent incubation of cells in darkness for 60 min, the D1 protein of the photoinactivated PSII was degraded. Further incubation in weak visible light resulted in the rapid restoration of the activity of PSII. These observations suggest that very strong UV-A light is a useful tool for the analysis of the repair of PSII after photoinactivation.
AB - When organisms that perform oxygenic photosynthesis are exposed to strong visible or UV light, inactivation of photosystem II (PSII) occurs. However, such organisms are able rapidly to repair the photoinactivated PSII. The phenomenon of photoinactivation and repair is known as photoinhibition. Under normal laboratory conditions, the rate of repair is similar to or faster than the rate of photoinactivation, preventing the detailed analysis of photoinactivation and repair as separate processes. We report here that, using strong UV-A light from a laser, we were able to analyze separately the photoinactivation and repair of photosystem II in the cyanobacterium Synechocystis sp. PCC 6803. Very strong UV-A light at 364 nm and a photon flux density of 2600 μmol photons m -2 s-1 inactivated the oxygen-evolving machinery and the photochemical reaction center of PSII within 1 or 2 min before the first step in the repair process, namely, the degradation of the D1 protein, occurred. During subsequent incubation of cells in weak visible light, the activity of PSII recovered fully within 30 min and this process depended on protein synthesis. During subsequent incubation of cells in darkness for 60 min, the D1 protein of the photoinactivated PSII was degraded. Further incubation in weak visible light resulted in the rapid restoration of the activity of PSII. These observations suggest that very strong UV-A light is a useful tool for the analysis of the repair of PSII after photoinactivation.
KW - D1 protein
KW - Photoinhibition
KW - Photosystem II
KW - Synechocystis
KW - UV-A light
UR - http://www.scopus.com/inward/record.url?scp=33645013992&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33645013992&partnerID=8YFLogxK
U2 - 10.1016/j.bbabio.2006.01.004
DO - 10.1016/j.bbabio.2006.01.004
M3 - Article
C2 - 16500615
AN - SCOPUS:33645013992
VL - 1757
SP - 123
EP - 129
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 2
ER -