Insertion domain within mammalian mitochondrial translation initiation factor 2 serves the role of eubacterial initiation factor 1

Aymen S. Yassin, Md Emdadul Haque, Partha P. Datta, Kevin Elmore, Nilesh K. Banavali, Linda L. Spremulli, Rajendra K. Agrawal

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Mitochondria have their own translational machineries for the synthesis of thirteen polypeptide chains that are components of the complexes that participate in the process of oxidative phosphorylation (or ATP generation). Translation initiation in mammalian mitochondria requires two initiation factors, IF2mt and IF3mt, instead of the three that are present in eubacteria. The mammalian IF2mt possesses a unique 37 amino acid insertion domain, which is known to be important for the formation of the translation initiation complex. We have obtained a three-dimensional cryoelectron microscopic map of the mammalian IF2mt in complex with initiator fMet-tRNAiMet and the eubacterial ribosome. We find that the 37 amino acid insertion domain interacts with the same binding site on the ribosome that would be occupied by the eubacterial initiation factor IF1, which is absent in mitochondria. Our finding suggests that the insertion domain of IF2mt mimics the function of eubacterial IF1, by blocking the ribosomal aminoacyl-tRNA binding site (A site) at the initiation step.

Original languageEnglish
Pages (from-to)3918-3923
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number10
DOIs
StatePublished - 8 Mar 2011
Externally publishedYes

Keywords

  • Molecular modeling
  • Protein synthesis
  • Ribosome-IF2 complex
  • cryo-EM structure

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