IUBMB Enzyme Nomenclature


Accepted name: rRNA small subunit pseudouridine methyltransferase Nep1

Reaction: S-adenosyl-L-methionine + pseudouridine1191 in yeast 18S rRNA = S-adenosyl-L-homocysteine + N1-methylpseudouridine1191 in yeast 18S rRNA

Other name(s): Nep1; nucleolar essential protein 1

Systematic name: S-adenosyl-L-methionine:18S rRNA (pseudouridine1191-N1)-methyltransferase

Comments: This enzyme, which occurs in both prokaryotes and eukaryotes, recognizes specific pseudouridine residues (Ψ) in small subunits of ribosomal RNA based on the local RNA structure. It recognizes Ψ914 in 16S rRNA from the archaeon Methanocaldococcus jannaschii, Ψ1191 in yeast 18S rRNA, and Ψ1248 in human 18S rRNA.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number:


1. Taylor, A.B., Meyer, B., Leal, B.Z., Kötter, P., Schirf, V., Demeler, B., Hart, P.J., Entian, K.-D. and Wöhnert, J. The crystal structure of Nep1 reveals an extended SPOUT-class methyltransferase fold and a pre-organized SAM-binding site. Nucleic Acids Res. 36 (2008) 1542-1554. [PMID: 18208838]

2. Wurm, J.P., Meyer, B., Bahr, U., Held, M., Frolow, O., Kötter, P., Engels, J.W., Heckel, A., Karas, M., Entian, K.-D. and Wöhnert, J. The ribosome assembly factor Nep1 responsible for Bowen-Conradi syndrome is a pseudouridine-N1-specific methyltransferase. Nucleic Acids Res. 38 (2010) 2387-2398. [PMID: 20047967]

3. Meyer, B., Wurm, J.P., Kötter, P., Leisegang, M.S., Schilling, V., Buchhaupt, M., Held, M., Bahr, U., Karas, M., Heckel, A., Bohnsack, M.T., Wöhnert, J. and Entian, K.-D. The Bowen-Conradi syndrome protein Nep1 (Emg1) has a dual role in eukaryotic ribosome biogenesis, as an essential assembly factor and in the methylation of Ψ1191 in yeast 18S rRNA. Nucleic Acids Res. 39 (2011) 1526-1537. [PMID: 20972225]

[EC created 2012]

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