Sequence divergence of seryl-tRNA synthetases in archaea

J Bacteriol. 1998 Dec;180(24):6446-9. doi: 10.1128/JB.180.24.6446-6449.1998.


The genomic sequences of Methanococcus jannaschii and Methanobacterium thermoautotrophicum contain a structurally uncommon seryl-tRNA synthetase (SerRS) sequence and lack an open reading frame (ORF) for the canonical cysteinyl-tRNA synthetase (CysRS). Therefore, it is not clear if Cys-tRNACys is formed by direct aminoacylation or by a transformation of serine misacylated to tRNACys. To address this question, we prepared SerRS from two methanogenic archaea and measured the enzymatic properties of these proteins. SerRS was purified from M. thermoautotrophicum; its N-terminal peptide sequence matched the sequence deduced from the relevant ORF in the genomic data of M. thermoautotrophicum and M. jannaschii. In addition, SerRS was expressed from a cloned Methanococcus maripaludis serS gene. The two enzymes charged serine to their homologous tRNAs and also accepted Escherichia coli tRNA as substrate for aminoacylation. Gel shift experiments showed that M. thermoautotrophicum SerRS did not mischarge tRNACys with serine. This indicates that Cys-tRNACys is formed by direct acylation in these organisms.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cloning, Molecular
  • DNA, Archaeal
  • Gene Expression
  • Humans
  • Methanobacterium / enzymology*
  • Methanobacterium / genetics
  • Methanococcus / enzymology*
  • Methanococcus / genetics
  • Molecular Sequence Data
  • RNA, Archaeal / metabolism
  • RNA, Transfer / metabolism
  • Sequence Homology, Amino Acid
  • Serine-tRNA Ligase / genetics*
  • Serine-tRNA Ligase / isolation & purification
  • Serine-tRNA Ligase / metabolism


  • DNA, Archaeal
  • RNA, Archaeal
  • RNA, Transfer
  • Serine-tRNA Ligase

Associated data

  • GENBANK/AF009822