Abstract
Light energy drives photosynthesis, but it simultaneously inactivates photosynthetic mechanisms. A major target site of photo-damage is photosystem II (PSII). It further targets one reaction center protein, D1, which is maintained efficiently by the PSII repair cycle. Two proteases, FtsH and Deg, are known to contribute to this process, respectively, by efficient degradation of photo-damaged D1 protein processively and endoproteolytically. This study tested whether the D1 cleavage accomplished by these proteases is affected by different monochromic lights such as blue and red light-emitting-diode light sources, remaining mindful that the use of these lights distinguishes the current models for photoinhibition: the excess-energy model and the two-step model. It is noteworthy that in the two-step model, primary damage results from the absorption of light energy in the Mn-cluster, which can be enhanced by a blue rather than a red light source. Results showed that blue and red lights affect D1 degradation differently. One prominent finding was that D1 fragmentation that is specifically generated by luminal Deg proteases was enhanced by blue light but not by red light in the mutant lacking FtsH2. Although circumstantial, this evidence supports a two-step model of PSII photo-damage. We infer that enhanced D1 fragmentation by luminal Deg proteases is a response to primary damage at the Mn-cluster.
| Original language | English |
|---|---|
| Pages (from-to) | 409-416 |
| Number of pages | 8 |
| Journal | Photosynthesis Research |
| Volume | 126 |
| Issue number | 2-3 |
| DOIs | |
| Publication status | Published - Apr 19 2015 |
Fingerprint
Keywords
- Chloroplast protease
- D1 degradation
- Deg
- FtsH
- Photoinhibition
- PSII repair
ASJC Scopus subject areas
- Plant Science
- Cell Biology
- Biochemistry
Cite this
D1 fragmentation in photosystem II repair caused by photo-damage of a two-step model. / Kato, Yusuke; Ozawa, Shinichiro; Takahashi, Yuichiro; Sakamoto, Wataru.
In: Photosynthesis Research, Vol. 126, No. 2-3, 19.04.2015, p. 409-416.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - D1 fragmentation in photosystem II repair caused by photo-damage of a two-step model
AU - Kato, Yusuke
AU - Ozawa, Shinichiro
AU - Takahashi, Yuichiro
AU - Sakamoto, Wataru
PY - 2015/4/19
Y1 - 2015/4/19
N2 - Light energy drives photosynthesis, but it simultaneously inactivates photosynthetic mechanisms. A major target site of photo-damage is photosystem II (PSII). It further targets one reaction center protein, D1, which is maintained efficiently by the PSII repair cycle. Two proteases, FtsH and Deg, are known to contribute to this process, respectively, by efficient degradation of photo-damaged D1 protein processively and endoproteolytically. This study tested whether the D1 cleavage accomplished by these proteases is affected by different monochromic lights such as blue and red light-emitting-diode light sources, remaining mindful that the use of these lights distinguishes the current models for photoinhibition: the excess-energy model and the two-step model. It is noteworthy that in the two-step model, primary damage results from the absorption of light energy in the Mn-cluster, which can be enhanced by a blue rather than a red light source. Results showed that blue and red lights affect D1 degradation differently. One prominent finding was that D1 fragmentation that is specifically generated by luminal Deg proteases was enhanced by blue light but not by red light in the mutant lacking FtsH2. Although circumstantial, this evidence supports a two-step model of PSII photo-damage. We infer that enhanced D1 fragmentation by luminal Deg proteases is a response to primary damage at the Mn-cluster.
AB - Light energy drives photosynthesis, but it simultaneously inactivates photosynthetic mechanisms. A major target site of photo-damage is photosystem II (PSII). It further targets one reaction center protein, D1, which is maintained efficiently by the PSII repair cycle. Two proteases, FtsH and Deg, are known to contribute to this process, respectively, by efficient degradation of photo-damaged D1 protein processively and endoproteolytically. This study tested whether the D1 cleavage accomplished by these proteases is affected by different monochromic lights such as blue and red light-emitting-diode light sources, remaining mindful that the use of these lights distinguishes the current models for photoinhibition: the excess-energy model and the two-step model. It is noteworthy that in the two-step model, primary damage results from the absorption of light energy in the Mn-cluster, which can be enhanced by a blue rather than a red light source. Results showed that blue and red lights affect D1 degradation differently. One prominent finding was that D1 fragmentation that is specifically generated by luminal Deg proteases was enhanced by blue light but not by red light in the mutant lacking FtsH2. Although circumstantial, this evidence supports a two-step model of PSII photo-damage. We infer that enhanced D1 fragmentation by luminal Deg proteases is a response to primary damage at the Mn-cluster.
KW - Chloroplast protease
KW - D1 degradation
KW - Deg
KW - FtsH
KW - Photoinhibition
KW - PSII repair
UR - http://www.scopus.com/inward/record.url?scp=84942831547&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84942831547&partnerID=8YFLogxK
U2 - 10.1007/s11120-015-0144-7
DO - 10.1007/s11120-015-0144-7
M3 - Article
C2 - 25893898
AN - SCOPUS:84942831547
VL - 126
SP - 409
EP - 416
JO - Photosynthesis Research
JF - Photosynthesis Research
SN - 0166-8595
IS - 2-3
ER -