Qbeta-phage resistance by deletion of the coiled-coil motif in elongation factor Ts

Research output: Contribution to journalArticle


Elongation factor Ts (EF-Ts) is the guanine-nucleotide exchange factor of elongation factor Tu (EF-Tu), which promotes the binding of aminoacyl-tRNA to the mRNA-programmed ribosome in prokaryotes. The EF-Tu.EF-Ts complex, one of the EF-Tu complexes during protein synthesis, is also a component of RNA-dependent RNA polymerases like the polymerase from coliphage Qbeta. The present study shows that the Escherichia coli mutant GRd.tsf lacking the coiled-coil motif of EF-Ts is completely resistant to phage Qbeta and that Qbeta-polymerase complex formation is not observed. GRd.tsf is the first E. coli mutant ever described that is unable to form a Qbeta-polymerase complex while still maintaining an almost normal growth behavior. The phage resistance correlates with an observed instability of the mutant EF-Tu.EF-Ts complex in the presence of guanine nucleotides. Thus, the mutant EF-Tu.EF-Ts is the first EF-Tu.EF-Ts complex ever described that is completely inactive in the Qbeta-polymerase complex despite its almost full activity in protein synthesis. We propose that the role of EF-Ts in the Qbeta-polymerase complex is to control and trap EF-Tu in a stable conformation with affinity for RNA templates while unable to bind aminoacyl-tRNA.


  • Henrik Karring
  • Sander G J Mathu
  • Jan van Duin
  • Brian F C Clark
  • Barend Kraal
  • Charlotte R Knudsen
External organisations
  • Aarhus University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Rheumatology and Autoimmunity
Original languageEnglish
Pages (from-to)1878-1884
JournalJournal of Biological Chemistry
Issue number3
Publication statusPublished - 2004
Publication categoryResearch
Externally publishedYes

Bibliographic note

The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Connective Tissue Biology (013230151)