Rubisco small and large subunit N-methyltransferases. Bi- and mono- functional methyltransferases that methylate the small and large subunits of Rubisco

Zhentu Ying, R. Michael Mulligan, Noel Janney, Robert L. Houtz

Research output: Contribution to journalArticlepeer-review

49 Scopus citations

Abstract

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco)is methylated at the α-amino group of the N-terminal methionine of the processed form of the small subunit (SS), and at the ε-amino group of lysine-14 of the large subunit (LS) in some species. The Rubisco LS methyltransferase (LSMT) gene has been cloned and expressed from pea and specifically methylates lysine-14 of the LS of Rubisco. We determine here that both pea and tobacco Rubisco LSMT also exhibit (α)N-methyltransferase activity toward the SS of Rubisco, suggesting that a single gene product can produce a bifunctional protein methyltransferase capable of catalyzing both (α)N-methylation of the SS and (ε)N-methylation of the LS. A homologue of the Rubisco LSMT gene (rbcMT-S) has also been identified in spinach that is closely related to Rubisco LSMT sequences from pea and tobacco. Two mRNAs are produced from rbcMT-S, and both long and short forms of the spinach cDNAs were expressed in Escherichia coli cells and shown to catalyze methylation of the α-amino group of the N- terminal methionine of the SS of Rubisco. Thus, the absence of lysine-14 methylation in species like spinach is apparently a consequence of a monofunctional protein methyltransferase incapable of methylating Lys-14, with activity limited to methylation of the SS.

Original languageEnglish
Pages (from-to)36750-36756
Number of pages7
JournalJournal of Biological Chemistry
Volume274
Issue number51
DOIs
StatePublished - Dec 17 1999

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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