Article

Structure determination of fibrillarin from the hyperthermophilic archaeon Pyrococcus furiosus.

Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
Biochemical and Biophysical Research Communications (impact factor: 2.48). 04/2004; 315(3):726-32. DOI:10.1016/j.bbrc.2004.01.114 pp.726-32
Source: PubMed

ABSTRACT The methyltransferase fibrillarin is the catalytic component of ribonucleoprotein complexes that direct site-specific methylation of precursor ribosomal RNA and are critical for ribosome biogenesis in eukaryotes and archaea. Here we report the crystal structure of a fibrillarin ortholog from the hyperthermophilic archaeon Pyrococcus furiosus at 1.97A resolution. Comparisons of the X-ray structures of fibrillarin orthologs from Methanococcus jannashii and Archaeoglobus fulgidus reveal nearly identical backbone configurations for the catalytic C-terminal domain with the exception of a unique loop conformation at the S-adenosyl-l-methionine (AdoMet) binding pocket in P. furiosus. In contrast, the N-terminal domains are divergent which may explain why some forms of fibrillarin apparently homodimerize (M. jannashii) while others are monomeric (P. furiosus and A. fulgidus). Three positively charged amino acids surround the AdoMet-binding site and sequence analysis indicates that this is a conserved feature of both eukaryotic and archaeal fibrillarins. We discuss the possibility that these basic residues of fibrillarin are important for RNA-guided rRNA methylation.

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Keywords

A. fulgidus
 
AdoMet-binding site
 
amino acids
 
archaeal fibrillarins
 
Archaeoglobus fulgidus
 
basic residues
 
catalytic C-terminal domain
 
catalytic component
 
conserved feature
 
fibrillarin orthologs
 
hyperthermophilic archaeon Pyrococcus furiosus
 
identical backbone configurations
 
M. jannashii
 
Methanococcus jannashii
 
N-terminal domains
 
precursor ribosomal RNA
 
ribonucleoprotein complexes
 
RNA-guided rRNA methylation
 
unique loop conformation
 
X-ray structures