1. Chlorophyll biosynthesis under the control of arginine metabolism
- Author
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Éva Kiss, Jana Talbot, Nathan B.P. Adams, Stanislav Opekar, Martin Moos, Jan Pilný, Tatjana Kvasov, Emilia Schneider, Peter Koník, Petr Šimek, and Roman Sobotka
- Subjects
CP: Plants ,Biology (General) ,QH301-705.5 - Abstract
Summary: In natural environments, photosynthetic organisms adjust their metabolism to cope with the fluctuating availability of combined nitrogen sources, a growth-limiting factor. For acclimation, the dynamic degradation/synthesis of tetrapyrrolic pigments, as well as of the amino acid arginine, is pivotal; however, there has been no evidence that these processes could be functionally coupled. Using co-immunopurification and spectral shift assays, we found that in the cyanobacterium Synechocystis sp. PCC 6803, the arginine metabolism-related ArgD and CphB enzymes form protein complexes with Gun4, an essential protein for chlorophyll biosynthesis. Gun4 binds ArgD with high affinity, and the Gun4-ArgD complex accumulates in cells supplemented with ornithine, a key intermediate of the arginine pathway. Elevated ornithine levels restricted de novo synthesis of tetrapyrroles, which arrested the recovery from nitrogen deficiency. Our data reveal a direct crosstalk between tetrapyrrole biosynthesis and arginine metabolism that highlights the importance of balancing photosynthetic pigment synthesis with nitrogen homeostasis.
- Published
- 2023
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