Qbeta-phage resistance by deletion of the coiled-coil motif in elongation factor Ts
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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.
|Research areas and keywords||
Subject classification (UKÄ) – MANDATORY
|Journal||Journal of Biological Chemistry|
|Publication status||Published - 2004|
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)