Dataset Information

Rubisco acetylation stoichiometry in Arabidopsis Thaliana

ABSTRACT: Multiple studies have shown Rubisco to be subject to Lys-acetylation at various residues; however, conflicting reports exist about the biological significance of these post-translational modifications. One aspect of the Lys-acetylation that has not been addressed in plants generally, or with Rubisco specifically, is the stoichiometry at which these Lys-acetylation events occur. As a method to ascertain which Lys-acetylation sites on Arabidopsis Rubisco might be of regulatory importance, we purified Rubisco from leaves in both the day and night-time and performed independent mass-spectrometry based methods to determine the stoichiometry of Rubisco Lys-acetylation events.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Arabidopsis Thaliana (mouse-ear Cress)

TISSUE(S): Leaf

SUBMITTER: Brendan O'Leary

LAB HEAD: Harvey Millar

PROVIDER: PXD019268 | Pride | 2020-09-28

REPOSITORIES: Pride

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Publications

Rubisco lysine acetylation occurs at very low stoichiometry in mature Arabidopsis leaves: implications for regulation of enzyme function.

O'Leary Brendan M BM Scafaro Andrew P AP Fenske Ricarda R Duncan Owen O Ströher Elke E Petereit Jakob J Millar A Harvey AH

The Biochemical journal 20201001 19

Multiple studies have shown ribulose-1,5-bisphosphate carboxylase/oxygenase (E.C. 4.1.1.39; Rubisco) to be subject to Lys-acetylation at various residues; however, opposing reports exist about the biological significance of these post-translational modifications. One aspect of the Lys-acetylation that has not been addressed in plants generally, or with Rubisco specifically, is the stoichiometry at which these Lys-acetylation events occur. As a method to ascertain which Lys-acetylation sites on A ...[more]

PMID: 32959870

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Project description:The slow kinetics and poor substrate specificity of the key photosynthetic CO2-fixing enzyme Rubisco have prompted the repeated evolution of Rubisco containing compartments known as pyrenoids in diverse algal lineages and carboxysomes in prokaryotes. Inside these compartments actively transported bicarbonate is converted into CO2 gas, which saturates the carboxylase with its substrate. Using co-immunoprecipitation experiments in Phaeodactylum tricornutum we have identified the Rubisco linker protein PYCO1. Similar to the green algal Rubisco linker protein EPYC1, PYCO1 is intrinsically disordered, possesses repeats and is positively charged at physiological pH. However, it possesses no sequence similarity to EPYC1, as expected for convergent evolution of a red Rubisco containing pyrenoid. Fluorescent PYCO1 fusion proteins localize as a rod shaped structure in the diatom chloroplast, consistent with the shape of the pyrenoid defined by transmission electron microscopy. To test the hypothesis that PYCO1 is the diatom pyrenoid scaffold we produced pure protein in Escherichia coli. Recombinant PYCO1 protein undergoes homotypic liquid liquid phase separation in a salt dependent manner. Diatom Rubisco specifically partitions into PYCO1 condensates. Heterotypic PYCO1-Rubisco condensates can bind up to three Rubisco hexadecamers per PYCO1 protein. Rubisco carboxylase function is unaffected in the condensates. PYCO1 is highly mobile in homotypic condensates. In contrast PYCO1 condensates saturated with diatom Rubisco have greatly reduced dynamics, with both PYCO1 and Rubisco becoming immobile. Consistently, FRAP experiments indicate that PYCO1 is not mobile in vivo. A combination of Cryo-electron microscopy and site-directed mutagenesis data show that the KWSP motif found in PYCO1 repeats binds to small subunits at the entrance of the Rubisco hexadecamer’s solvent channel. Analysis of mutant PYCO1 proteins show that both the “KWSP” tryptophan and another repeating tyrosine are essential for homotypic phase separation. We speculate that the unusual material properties of the PYCO1-Rubisco condensate are necessary to support the unusual non-spherical shape of the Phaeodactylum pyrenoid. Careful characterization of multiple diverse Rubisco condensates will strengthen translational approaches aiming to introduce pyrenoids and other metabolic condensates into new host organisms.

Project description:Background: Lysine crotonylation (Kcr), as a novel evolutionarily conserved type of PTM, is ubiquitous and essential in cell biology. However, its functions in tea plant, an important beverage crop, are largely unknown. Our study firstly attempted to describe Kcr proteins in tea leaves under NH4+ deficiency/resupply, and provided significant insights into exploring the physiological role of Kcr in plants for N utilization. Results: We performed the global analysis of crotonylome in tea plants under NH4+ deficiency/resupply using high-resolution LC-MS/MS coupled with highly sensitive immune-antibody. A total of 2288 kcr sites on 971 proteins were identified, of which contained in 15 types of Kcr motifs. Most of Kcr proteins were located in chloroplast and cytoplasm. 120 and 151 Kcr proteins were significantly changed at 3 hours and 3days of NH4+ resupply, respectively. Bioinformatics analysis showed that differentially expressed Kcr proteins participated in diverse biological processes such as photosynthesis, carbon fixation and amino acid metabolism, suggesting Kcr plays important roles in these processes. Interestingly, a large number of enzymes were crotonylated, and the activity and Kcr level of these enzymes changed significantly after NH4+ resupply, indicating a potential function of Kcr in the regulation of enzyme activities. Moreover, the protein-protein interaction analysis revealed that the diverse interactions of identified Kcr proteins mainly involved in photosynthesis, carbon fixation, amino acid metabolism and ribosome. Conclusions: The results suggested that lysine crotonylated proteins might play regulating roles in metabolic process in tea leaves under NH4+ deficiency/resupply. The critical regulatory roles mainly involved in diverse aspects of primary metabolic processes, especially in photosynthesis, carbon fixation and amino acid metabolism. The provided data may serve as important resources for exploring the physiological, biochemical, and genetic role of lysine crotonylation in tea plants.

Dataset Information

Rubisco acetylation stoichiometry in Arabidopsis Thaliana

Publications

Rubisco lysine acetylation occurs at very low stoichiometry in mature Arabidopsis leaves: implications for regulation of enzyme function.

Similar Datasets

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