The structure of the RlmB 23S rRNA methyltransferase reveals a new methyltransferase fold with a unique knot

Structure. 2002 Oct;10(10):1303-15. doi: 10.1016/s0969-2126(02)00852-3.


In Escherichia coli, RlmB catalyzes the methylation of guanosine 2251, a modification conserved in the peptidyltransferase domain of 23S rRNA. The crystal structure of this 2'O-methyltransferase has been determined at 2.5 A resolution. RlmB consists of an N-terminal domain connected by a flexible extended linker to a catalytic C-terminal domain and forms a dimer in solution. The C-terminal domain displays a divergent methyltransferase fold with a unique knotted region, and lacks the classic AdoMet binding site features. The N-terminal domain is similar to ribosomal proteins L7 and L30, suggesting a role in 23S rRNA recognition. The conserved residues in this novel family of 2'O-methyltransferases cluster in the knotted region, suggesting the location of the catalytic and AdoMet binding sites.

MeSH terms

  • Amino Acid Sequence
  • Catalytic Domain
  • Dimerization
  • Escherichia coli / enzymology*
  • Methyltransferases / chemistry*
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Folding
  • RNA, Ribosomal, 23S / chemistry
  • Sequence Homology, Amino Acid


  • RNA, Ribosomal, 23S
  • Methyltransferases
  • rRNA (adenosine-O-2'-)methyltransferase

Associated data

  • PDB/1GZ0