title: The structure of the box C/D enzyme reveals regulation of RNA methylation.
abstract: Post-transcriptional modifications are essential to the cell life cycle, as they affect both pre-ribosomal RNA processing and ribosome assembly. The box C/D ribonucleoprotein enzyme that methylates ribosomal RNA at the 2'-O-ribose uses a multitude of guide RNAs as templates for the recognition of rRNA target sites. Two methylation guide sequences are combined on each guide RNA, the significance of which has remained unclear. Here we use a powerful combination of NMR spectroscopy and small-angle neutron scattering to solve the structure of the 390 kDa archaeal RNP enzyme bound to substrate RNA. We show that the two methylation guide sequences are located in different environments in the complex and that the methylation of physiological substrates targeted by the same guide RNA occurs sequentially. This structure provides a means for differential control of methylation levels at the two sites and at the same time offers an unexpected regulatory mechanism for rRNA folding.
authors.affiliation: European Molecular Biology Laboratory, Structural and Computational Biology Unit, Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
authors.forename: Audrone
authors.initials: A
authors.lastname: Lapinaite
authors.forename: Bernd
authors.initials: B
authors.lastname: Simon
authors.forename: Lars
authors.initials: L
authors.lastname: Skjaerven
authors.forename: Magdalena
authors.initials: M
authors.lastname: Rakwalska-Bange
authors.forename: Frank
authors.initials: F
authors.lastname: Gabel
authors.forename: Teresa
authors.initials: T
authors.lastname: Carlomagno
mesh_terms: D001059:Apoproteins / Q000737:chemistry / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism; D055162:Biocatalysis; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D008745:Methylation; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism; D009690:Nucleic Acid Conformation; D020027:Pyrococcus furiosus / Q000201:enzymology* / Q000235:genetics*; D059370:RNA Folding; D012323:RNA Processing, Post-Transcriptional; D019642:RNA, Archaeal / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012335:RNA, Ribosomal / Q000737:chemistry* / Q000378:metabolism*; D020718:Ribonucleoproteins, Small Nucleolar / Q000737:chemistry* / Q000378:metabolism*; D058727:RNA, Small Untranslated
chemical_list: D001059:Apoproteins; D019843:Archaeal Proteins; D002868:Chromosomal Proteins, Non-Histone; D046912:Multiprotein Complexes; D019642:RNA, Archaeal; D012335:RNA, Ribosomal; D020718:Ribonucleoproteins, Small Nucleolar; C047458:fibrillarin; D058727:RNA, Small Untranslated