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

Brendan M. O’Leary*, Andrew P. Scafaro, Ricarda Fenske, Owen Duncan, Elke Ströher, Jakob Petereit, A. Harvey Millar

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    12 Citations (Scopus)

    Abstract

    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 Arabidopsis Rubisco might be of regulatory importance to its catalytic function in the Calvin–Benson cycle, 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. The results indicate that Rubisco is acetylated at most Lys residues, but each acetylation event occurs at very low stoichiometry. Furthermore, in vitro treatments that increased the extent of Lys-acetylation on purified Rubisco had no effect on Rubisco maximal activity. Therefore, we are unable to confirm that Lys-acetylation at low stoichiometries can be a regulatory mechanism controlling Rubisco maximal activity. The results highlight the need for further use of stoichiometry measurements when determining the biological significance of reversible PTMs like acetylation.

    Original languageEnglish
    Pages (from-to)3885-3896
    Number of pages12
    JournalBiochemical Journal
    Volume477
    Issue number19
    DOIs
    Publication statusPublished - Oct 2020

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