2v3j
The yeast ribosome synthesis factor Emg1 alpha beta knot fold methyltransferase
Structural highlights
FunctionNEP1_YEAST S-adenosyl-L-methionine-dependent pseudouridine N(1)-methyltransferase that methylates pseudouridine at position 1189 (Psi1189) in 18S rRNA. Involved the biosynthesis of the hypermodified N1-methyl-N3-(3-amino-3-carboxypropyl) pseudouridine (m1acp3-Psi) conserved in eukaryotic 18S rRNA. N1-methylation is independent on acp-modification at the N3-position of U1191. Has also an essential role in 40S ribosomal subunit biogenesis independent on its methyltransferase activity, facilitating the incorporation of ribosomal protein S19 (RPS19A/RPS19B) during the formation of pre-ribosomes.[1] [2] [3] [4] [5] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedEmg1 was previously shown to be required for maturation of the 18S rRNA and biogenesis of the 40S ribosomal subunit. Here we report the determination of the crystal structure of Emg1 at 2 A resolution in complex with the methyl donor, S-adenosyl-methionine (SAM). This structure identifies Emg1 as a novel member of the alpha/beta knot fold methyltransferase (SPOUT) superfamily. In addition to the conserved SPOUT core, Emg1 has two unique domains that form an extended surface, which we predict to be involved in binding of RNA substrates. A point mutation within a basic patch on this surface almost completely abolished RNA binding in vitro. Three point mutations designed to disrupt the interaction of Emg1 with SAM each caused>100-fold reduction in SAM binding in vitro. Expression of only Emg1 with these mutations could support growth and apparently normal ribosome biogenesis in strains genetically depleted of Emg1. We conclude that the catalytic activity of Emg1 is not essential and that the presence of the protein is both necessary and sufficient for ribosome biogenesis. The yeast ribosome synthesis factor Emg1 is a novel member of the superfamily of alpha/beta knot fold methyltransferases.,Leulliot N, Bohnsack MT, Graille M, Tollervey D, Van Tilbeurgh H Nucleic Acids Res. 2008 Feb;36(2):629-39. Epub 2007 Dec 6. PMID:18063569[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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