EMD-1854
An insertion domain within mammalian mitochondrial translation initiation factor 2 serves the role of eubacterial initiation factor 1
EMD-1854
Single-particle10.8 Å
Deposition: 05/01/2011Map released: 11/03/2011
Last modified: 24/10/2012
Sample Organism:
Escherichia coli,
Bos taurus
Sample: E. coli 70S ribosome in complex with a mammalian mitochondrial translation initiation factor 2 and initiator transfer RNA
Fitted models: 3izz (Avg. Q-score: -0.003)
Deposition Authors: Yassin AS
,
Haque E,
Datta PP ,
Elmore K ,
Banavali NK ,
Spremulli LL,
Agrawal RK
Sample: E. coli 70S ribosome in complex with a mammalian mitochondrial translation initiation factor 2 and initiator transfer RNA
Fitted models: 3izz (Avg. Q-score: -0.003)
Deposition Authors: Yassin AS
,
Haque E,
Datta PP ,
Elmore K ,
Banavali NK ,
Spremulli LL,
Agrawal RK
Insertion domain within mammalian mitochondrial translation initiation factor 2 serves the role of eubacterial initiation factor 1.
Yassin AS ,
Haque ME,
Datta PP ,
Elmore K ,
Banavali NK ,
Spremulli LL,
Agrawal RK
(2011) PNAS , 108 , 3918 - 3923
,
Haque ME,
Datta PP ,
Elmore K ,
Banavali NK ,
Spremulli LL,
Agrawal RK
(2011) PNAS , 108 , 3918 - 3923
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, IF2(mt) and IF3(mt), instead of the three that are present in eubacteria. The mammalian IF2(mt) 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 IF2(mt) in complex with initiator fMet-tRNA(iMet) 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 IF2(mt) mimics the function of eubacterial IF1, by blocking the ribosomal aminoacyl-tRNA binding site (A site) at the initiation step.
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, IF2(mt) and IF3(mt), instead of the three that are present in eubacteria. The mammalian IF2(mt) 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 IF2(mt) in complex with initiator fMet-tRNA(iMet) 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 IF2(mt) mimics the function of eubacterial IF1, by blocking the ribosomal aminoacyl-tRNA binding site (A site) at the initiation step.