ArticleThe Journal of biological chemistry2015
Porphyrin Binding to Gun4 Protein, Facilitated by a Flexible Loop, Controls Metabolite Flow through the Chlorophyll Biosynthetic Pathway.
Article in The Journal of biological chemistry, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 19 papers.
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Who cites it
19 citing papers in PubMed, 34 citations in OpenAlex.
- Exceptionally selective voltage-sensor trapping of NaScientific reports · 2026Article
- Article
- Chlorophyll biosynthesis under the control of arginine metabolism.Cell reports · 2023Article
- Absolute quantification of cellular levels of photosynthesis-related proteins in Synechocystis sp. PCC 6803.Photosynthesis research · 2023Article
- Transcriptome analyses reveal photosynthesis-related genes involved in photosynthetic regulation under low temperature stress inFrontiers in plant science · 2023Article
- Biophysical Approaches for the Characterization of Protein-Metabolite Interactions.Methods in molecular biology (Clifton, N.J.) · 2023Review
- Impact of Porphyrin Binding to GENOMES UNCOUPLED 4 on Tetrapyrrole BiosynthesisFrontiers in plant science · 2022Article
- Macroscopic variation in Arabidopsis mutants despite stomatal uniformity across soil nutrient environments.Genetica · 2021Article
- The Papain-like Cysteine ProteaseInternational journal of molecular sciences · 2021Article
- Structural basis of bilin binding by the chlorophyll biosynthesis regulator GUN4.Protein science : a publication of the Protein Society · 2021Article
- Bilin-dependent regulation of chlorophyll biosynthesis by GUN4.Proceedings of the National Academy of Sciences of the United States of America · 2021Article
- Evolution of Ycf54-independent chlorophyll biosynthesis in cyanobacteria.Proceedings of the National Academy of Sciences of the United States of America · 2021Article
- A Photosynthesis-Specific Rubredoxin-Like Protein Is Required for Efficient Association of the D1 and D2 Proteins during the Initial Steps of Photosystem II Assembly.The Plant cell · 2019Article
- The antenna-like domain of the cyanobacterial ferrochelatase can bind chlorophyll and carotenoids in an energy-dissipative configuration.The Journal of biological chemistry · 2019Article
- Adaptive simulations, towards interactive protein-ligand modeling.Scientific reports · 2017Article
- Three classes of oxygen-dependent cyclase involved in chlorophyll and bacteriochlorophyll biosynthesis.Proceedings of the National Academy of Sciences of the United States of America · 2017Article
- Exploring Binding Mechanisms in Nuclear Hormone Receptors by Monte Carlo and X-ray-derived Motions.Biophysical journal · 2017Article
- Phosphorylation of GENOMES UNCOUPLED 4 Alters Stimulation of Mg Chelatase Activity in Angiosperms.Plant physiology · 2016Article
- Transcriptional Regulation of Tetrapyrrole Biosynthesis inFrontiers in plant science · 2016Review
Corrections and comments
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Authors and funding
8 authors at 4 institutions in 3 countries.
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Abstract
In oxygenic phototrophs, chlorophylls, hemes, and bilins are synthesized by a common branched pathway. Given the phototoxic nature of tetrapyrroles, this pathway must be tightly regulated, and an important regulatory role is attributed to magnesium chelatase enzyme at the branching between the heme and chlorophyll pathway. Gun4 is a porphyrin-binding protein known to stimulate in vitro the magnesium chelatase activity, but how the Gun4-porphyrin complex acts in the cell was unknown. To address this issue, we first performed simulations to determine the porphyrin-docking mechanism to the cyanobacterial Gun4 structure. After correcting crystallographic loop contacts, we determined the binding site for magnesium protoporphyrin IX. Molecular modeling revealed that the orientation of α6/α7 loop is critical for the binding, and the magnesium ion held within the porphyrin is coordinated by Asn-211 residue. We also identified the basis for stronger binding in the Gun4-1 variant and for weaker binding in the W192A mutant. The W192A-Gun4 was further characterized in magnesium chelatase assay showing that tight porphyrin binding in Gun4 facilitates its interaction with the magnesium chelatase ChlH subunit. Finally, we introduced the W192A mutation into cells and show that the Gun4-porphyrin complex is important for the accumulation of ChlH and for channeling metabolites into the chlorophyll biosynthetic pathway.
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