Pseudouridine at position 55 in tRNA controls the contents of other modified nucleotides for low-temperature adaptation in the extreme-thermophilic eubacterium Thermus thermophilus

Nucleic Acids Res. 2011 Mar;39(6):2304-18. doi: 10.1093/nar/gkq1180. Epub 2010 Nov 18.


Pseudouridine at position 55 (Ψ55) in eubacterial tRNA is produced by TruB. To clarify the role of the Ψ55 modification, we constructed a truB gene disruptant (ΔtruB) strain of Thermus thermophilus which is an extreme-thermophilic eubacterium. Unexpectedly, the ΔtruB strain exhibited severe growth retardation at 50 °C. We assumed that these phenomena might be caused by lack of RNA chaperone activity of TruB, which was previously hypothetically proposed by others. To confirm this idea, we replaced the truB gene in the genome with mutant genes, which express TruB proteins with very weak or no enzymatic activity. However the growth retardation at 50 °C was not rescued by these mutant proteins. Nucleoside analysis revealed that Gm18, m(5)s(2)U54 and m(1)A58 in tRNA from the ΔtruB strain were abnormally increased. An in vitro assay using purified tRNA modification enzymes demonstrated that the Ψ55 modification has a negative effect on Gm18 formation by TrmH. These experimental results show that the Ψ55 modification is required for low-temperature adaptation to control other modified. (35)S-Met incorporation analysis showed that the protein synthesis activity of the ΔtruB strain was inferior to that of the wild-type strain and that the cold-shock proteins were absence in the ΔtruB cells at 50°C.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Intramolecular Transferases / genetics
  • Intramolecular Transferases / metabolism*
  • Methionine / metabolism
  • Molecular Chaperones / metabolism
  • Mutation
  • Nucleotides / chemistry
  • Nucleotides / metabolism
  • Pseudouridine / metabolism*
  • RNA Processing, Post-Transcriptional
  • RNA, Transfer / chemistry
  • RNA, Transfer / metabolism*
  • RNA, Transfer, Met / chemistry
  • Temperature*
  • Thermus thermophilus / enzymology*
  • Thermus thermophilus / genetics
  • Thermus thermophilus / growth & development
  • tRNA Methyltransferases / metabolism


  • Bacterial Proteins
  • Molecular Chaperones
  • Nucleotides
  • RNA, Transfer, Met
  • Pseudouridine
  • RNA, Transfer
  • Methionine
  • tRNA Methyltransferases
  • Intramolecular Transferases
  • pseudouridine synthases