The activity of a yeast Family 16 methyltransferase, Efm2, is affected by a conserved tryptophan and its N‐terminal region

Abstract

The Family 16 methyltransferases are a group of eukaryotic nonhistone protein methyltransferases. Sixteen of these have recently been described in yeast and human, but little is known about their sequence and structural features. Here we investigate one of these methyltransferases, Saccharomyces cerevisiae elongation factor methyltransferase 2 (Efm2), by site‐directed mutagenesis and truncation. We show that an active site‐associated tryptophan, invariant in Family 16 methyltransferases and at position 222 in Efm2, is important for methyltransferase activity. A second highly conserved tryptophan, at position 318 in Efm2, is likely involved in S‐adenosyl methionine binding but is of lesser consequence for catalysis. By truncation analysis, we show that the N‐terminal 50–200 amino acids of Efm2 are critical for its methyltransferase activity. As N‐terminal regions are variable among Family 16 methyltransferases, this suggests a possible role in determining substrate specificity. This is consistent with recently solved structures that show the core of Family 16 methyltransferases to be near‐identical but the N termini to be structurally quite different. Finally, we show that Efm2 can exist as an oligomer but that its N terminus is not necessary for oligomerisation to occur.

METTL21B Is a Novel Human Lysine Methyltransferase of Translation Elongation Factor 1A: Discovery by CRISPR/Cas9 Knockout

“…Despite its close relation to the other METTL21 proteins (METTL21A, C and D), METTL21B has a different substrate to both METTL21A (HSPA-KMT) and METTL21D (VCP-KMT). The main difference between these proteins is their N-terminal regions, beyond the core catalytic seven-beta-strand fold, which may therefore be responsible determining their substrate specificities (59). Nonetheless, their substrate proteins, eEF1A, Hsp70s and VCP, are all involved in protein quality control and homeostasis.…”

Eukaryote-Conserved Methylarginine Is Absent in Diplomonads and Functionally Compensated inGiardia

“…Two G. duodenalis Class I MTases (GL_100959, DHA_151673) were homologous to family 16 (MTF16) METTL21 K-MTases ( Hamey, Hart-Smith, et al. 2016 ).…”

“…2012 ), and DHA_151673 encoded the MTF16 catalytic methylation motif, “D/ExxF/Y” ( Kernstock et al. 2012 ; Hamey, Hart-Smith, et al. 2016 ).…”

Computational modeling reveals key molecular properties and dynamic behavior of disruptor of telomeric silencing 1‐like (DOT1L) and partnering complexes involved in leukemogenesis

“…This fold is present in myriad proteins across all kingdoms of life where they modify not only proteins but also lipids and small molecules 15–17 . Recent studies have led to the discovery of novel 7BS lysine MTases (KMTs), like those that belong to the yeast MTase family 16 (MTF16) which methylate lysine residues in non‐histone proteins 18,19 . Therefore, studying the biophysical and biochemical features of DOT1L is important to understand the mechanistic functions of DOT1L and these related KMTs at a fundamental level, in addition to the role of DOT1L in leukemogenesis 12 …”