open access

https://hdl.handle.net/2115/90640

Enrichment of chlorophyll catabolic enzymes in grana margins and their cooperation in catabolic reactions

英語

Grana margin

2021-11-01

Elsevier

Journal of plant physiology

266

153535

During leaf senescence, chlorophyll a and b are degraded through several enzymatic reactions, including chlorophyll b reductase, 7-hydroxymethyl chlorophyll a reductase, and Mg-dechelatase. Considering that the intermediates of the chlorophyll breakdown pathway are highly photoreactive, cooperative and efficient reactions of chlorophyll metabolic enzymes may protect chloroplasts from potential photo-oxidative damage. Here, we investigated the sub-organellar localization and cooperative reactions of the enzymes involved in the chlorophyll breakdown pathway by the fractionation of thylakoid membranes and enzymatic assays using recombinant proteins. We found that these enzymes were enriched in the grana margin fraction. Furthermore, we found that chlorophyll b reductase and Mg-dechelatase efficiently catabolized chlorophylls bound to the chlorophyll-protein complexes when these two enzymes were mixed. These results suggest that the co-localization of chlorophyll catabolic enzymes enables efficient chlorophyll breakdown. The results from this study highlight a key step forward in the investigation of the photosystem breakdown process.

学術雑誌論文

Accepted Manuscript

Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International

©2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/

0176-1617