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Participation of Chlorophyll b Reductase in the Initial Step of the Degradation of Light-harvesting Chlorophyll a/b-Protein Complexes in Arabidopsis
| Title: | Participation of Chlorophyll b Reductase in the Initial Step of the Degradation of Light-harvesting Chlorophyll a/b-Protein Complexes in Arabidopsis |
| Authors: | Horie, Yukiko Browse this author | | Ito, Hisashi Browse this author | | Kusaba, Makoto Browse this author | | Tanaka, Ryouichi Browse this author →KAKEN DB | | Tanaka, Ayumi Browse this author →KAKEN DB |
| Issue Date: | 26-Jun-2009 |
| Publisher: | American Society for Biochemistry and Molecular Biology |
| Journal Title: | Journal of Biological Chemistry |
| Volume: | 284 |
| Issue: | 26 |
| Start Page: | 17449 |
| End Page: | 17456 |
| Publisher DOI: | 10.1074/jbc.M109.008912 |
| Abstract: | The light-harvesting chlorophyll a/b-protein complex of photosystem II (LHCII) is the most abundant membrane protein in green plants, and its degradation is a crucial process for the acclimation to high light conditions and for the recovery of nitrogen (N) and carbon (C) during senescence. However, the molecular mechanism of LHCII degradation is largely unknown. Here, we report that chlorophyll b reductase, which catalyzes the first step of chlorophyll b degradation, plays a central role in LHCII degradation. When the genes for chlorophyll b reductases NOL and NYC1 were disrupted in Arabidopsis thaliana, chlorophyll b and LHCII were not degraded during senescence, whereas other pigment complexes completely disappeared. When purified trimeric LHCII was incubated with recombinant chlorophyll b reductase (NOL), expressed in Escherichia coli, the chlorophyll b in LHCII was converted to 7-hydroxymethyl chlorophyll a. Accompanying this conversion, chlorophylls were released from LHCII apoproteins until all the chlorophyll molecules in LHCII dissociated from the complexes. Chlorophyll-depleted LHCII apoproteins did not dissociate into monomeric forms but remained in the trimeric form. Based on these results, we propose the novel hypothesis that chlorophyll b reductase catalyzes the initial step of LHCII degradation, and that trimeric LHCII is a substrate of LHCII degradation. |
| Rights: | © 2009 by The American Society for Biochemistry and Molecular Biology, Inc. |
| Type: | article |
| URI: | http://hdl.handle.net/2115/38777 |
| Appears in Collections: | 低温科学研究所 (Institute of Low Temperature Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 田中 歩
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