Bilin-dependent regulation of chlorophyll biosynthesis by GUN4
| Autor: | Robert D. Willows, Rui Deng, Weida Shi, Weiqing Zhang, J. Clark Lagarias, Yan Wang, Qiuling Fan, Nathan C. Rockwell, Shelley S. Martin, Zheng Li, Yunling Guo, Mengqi Li, Deqiang Duanmu |
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| Rok vydání: | 2021 |
| Předmět: |
Chlorophyll
0106 biological sciences 0301 basic medicine HMOX1 Lyases Protoporphyrins Chlamydomonas reinhardtii Cyanobacteria 01 natural sciences 03 medical and health sciences chemistry.chemical_compound Bile Pigments Bilin Heme Multidisciplinary biology Protoporphyrin IX Intracellular Signaling Peptides and Proteins Biological Sciences biology.organism_classification Heme oxygenase 030104 developmental biology Magnesium chelatase Biochemistry chemistry Heme Oxygenase (Decyclizing) Protoporphyrin 010606 plant biology & botany |
| Zdroj: | Proc Natl Acad Sci U S A |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.2104443118 |
| Popis: | Biosyntheses of chlorophyll and heme in oxygenic phototrophs share a common trunk pathway that diverges with insertion of magnesium or iron into the last common intermediate, protoporphyrin IX. Since both tetrapyrroles are pro-oxidants, it is essential that their metabolism is tightly regulated. Here, we establish that heme-derived linear tetrapyrroles (bilins) function to stimulate the enzymatic activity of magnesium chelatase (MgCh) via their interaction with GENOMES UNCOUPLED 4 (GUN4) in the model green alga Chlamydomonas reinhardtii. A key tetrapyrrole-binding component of MgCh found in all oxygenic photosynthetic species, CrGUN4, also stabilizes the bilin-dependent accumulation of protoporphyrin IX-binding CrCHLH1 subunit of MgCh in light-grown C. reinhardtii cells by preventing its photooxidative inactivation. Exogenous application of biliverdin IXα reverses the loss of CrCHLH1 in the bilin-deficient heme oxygenase (hmox1) mutant, but not in the gun4 mutant. We propose that these dual regulatory roles of GUN4:bilin complexes are responsible for the retention of bilin biosynthesis in all photosynthetic eukaryotes, which sustains chlorophyll biosynthesis in an illuminated oxic environment. |
| Databáze: | OpenAIRE |
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