A bacterial elongation factor G homologue exclusively functions in ribosome recycling in the spirochaete Borrelia burgdorferi

Takuma Suematsu, Shin Ichi Yokobori, Hiroyuki Morita, Shigeo Yoshinari, Takuya Ueda, Kiyoshi Kita, Nono Takeuchi, Yoh Ichi Watanabe

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Translation elongation factor G (EF-G) in bacteria plays two distinct roles in different phases of the translation system. EF-G catalyses the translocation of tRNAs on the ribosome in the elongation step, as well as the dissociation of the post-termination state ribosome into two subunits in the recycling step. In contrast to this conventional view, it has very recently been demonstrated that the dual functions of bacterial EF-G are distributed over two different EF-G paralogues in human mitochondria. In the present study, we show that the same division of roles of EF-G is also found in bacteria. Two EF-G paralogues are found in the spirochaete Borrelia burgdorferi, EF-G1 and EF-G2. We demonstrate that EF-G1 is a translocase, while EF-G2 is an exclusive recycling factor. We further demonstrate that B. burgdorferi EF-G2 does not require GTP hydrolysis for ribosome disassembly, provided that translation initiation factor 3 (IF-3) is present in the reaction. These results indicate that two B. burgdorferi EF-G paralogues are close relatives to mitochondrial EF-G paralogues rather than the conventional bacterial EF-G, in both their phylogenetic and biochemical features.

Original languageEnglish
Pages (from-to)1445-1454
Number of pages10
JournalMolecular Microbiology
Issue number6
Publication statusPublished - 2010 Jan 1
Externally publishedYes


ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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