The crystal structure of Nep1 reveals an extended SPOUT-class methyltransferase fold and a pre-organized SAM-binding site

Ribosome biogenesis in eukaryotes requires the participation of a large number of ribosome assembly factors. The highly conserved eukaryotic nucleolar protein Nep1 has an essential but unknown function in 18S rRNA proces
Ribosome biogenesis in eukaryotes requires the participation of a large number of ribosome assembly factors. The highly conserved eukaryotic nucleolar protein Nep1 has an essential but unknown function in 18S rRNA processing and ribosome biogenesis. In Saccharomyces cerevisiae the malfunction of a temperature-sensitive Nep1 protein (nep1-1ts) was suppressed by the addition of S-adenosylmethionine (SAM). This suggests the participation of Nep1 in a methyltransferase reaction during ribosome biogenesis. In addition, yeast Nep1 binds to a 6-nt RNA-binding motif also found in 18S rRNA and facilitates the incorporation of ribosomal protein Rps19 during the formation of pre-ribosomes. Here, we present the X-ray structure of the Nep1 homolog from the archaebacterium Methanocaldococcus jannaschii in its free form (2.2 Å resolution) and bound to the S-adenosylmethionine analog S-adenosylhomocysteine (SAH, 2.15 Å resolution) and the antibiotic and general methyltransferase inhibitor sinefungin (2.25 Å resolution). The structure reveals a fold which is very similar to the conserved core fold of the SPOUT-class methyltransferases but contains a novel extension of this common core fold. SAH and sinefungin bind to Nep1 at a preformed binding site that is topologically equivalent to the cofactor-binding site in other SPOUT-class methyltransferases. Therefore, our structures together with previous genetic data suggest that Nep1 is a genuine rRNA methyltransferase.
show moreshow less

Export metadata

  • Export Bibtex
  • Export RIS
Metadaten
Author:Alexander B. Taylor, Britta Meyer, Belinda Z. Leal, Peter Kötter, Virgil Schirf, Borries Demeler, P. John Hart, Karl-Dieter Entian, Jens Wöhnert
URN:urn:nbn:de:hebis:30-57907
DOI:http://dx.doi.org/10.1093/nar/gkm1172
ISSN:1362-4962
ISSN:0305-1048
Pubmed Id:http://www.ncbi.nlm.nih.gov/pubmed?term=18208838
Parent Title (English):Nucleic acids research
Publisher:Oxford Univ. Press
Place of publication:Oxford
Document Type:Article
Language:English
Date of Publication (online):2008/10/01
Date of first Publication:2008/01/21
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2008/10/01
Volume:36
Issue:5
Pagenumber:14
First Page:1542
Last Page:1554
Note:
© 2008 The Author(s) This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 
Source:Nucleic Acids Research, 2008, Vol. 36, No. 5 1542-1554 doi:10.1093/nar/gkm1172
HeBIS PPN:205909280
Institutes:Biowissenschaften
Dewey Decimal Classification:570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Sondersammelgebiets-Volltexte
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell 2.0

$Rev: 11761 $