Substrate requirements for ErmC' methyltransferase activity

J Bacteriol. 1995 Aug;177(15):4327-32. doi: 10.1128/jb.177.15.4327-4332.1995.


ErmC' is a methyltransferase that confers resistance to the macrolide-lincosamide-streptogramin B group of antibiotics by catalyzing the methylation of 23S rRNA at a specific adenine residue (A-2085 in Bacillus subtilis; A-2058 in Escherichia coli). The gene for ErmC' was cloned and expressed to a high level in E. coli, and the protein was purified to virtual homogeneity. Studies of substrate requirements of ErmC' have shown that a 262-nucleotide RNA fragment within domain V of B. subtilis 23S rRNA can be utilized efficiently as a substrate for methylation at A-2085. Kinetic studies of the monomethylation reaction showed that the apparent Km of this 262-nucleotide RNA oligonucleotide was 26-fold greater than the value determined for full-size and domain V 23S rRNA. In addition, the Vmax for this fragment also rose sevenfold. A model of RNA-ErmC' interaction involving multiple binding sites is proposed from the kinetic data presented.

MeSH terms

  • Bacillus subtilis / enzymology*
  • Bacillus subtilis / genetics
  • Base Sequence
  • Gene Expression Regulation, Bacterial
  • Kinetics
  • Methylation
  • Methyltransferases / genetics
  • Methyltransferases / metabolism*
  • Molecular Sequence Data
  • Nucleic Acid Conformation
  • Oligodeoxyribonucleotides / metabolism
  • Peptidyl Transferases / genetics
  • Peptidyl Transferases / metabolism
  • RNA, Bacterial / metabolism
  • RNA, Ribosomal, 23S / metabolism
  • Substrate Specificity


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