A Single Mammalian Mitochondrial Translation Initiation Factor Functionally Replaces Two Bacterial Factors

Gaur, Rahul and Grasso, Domenick and Datta, Partha P and Krishna, PDV and Das, Gautam and Spencer, Angela and Agrawal, Rajendra K and Spremulli, Linda and Varshney, Umesh (2008) A Single Mammalian Mitochondrial Translation Initiation Factor Functionally Replaces Two Bacterial Factors. In: Molecular Cell, 29 (2). pp. 180-190.

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Abstract

The mechanism of translation in eubacteria and organelles is thought to be similar. In eubacteria, the three initiation factors IF1, IF2, and IF3 are vital. Although the homologs of IF2 and IF3 are found in mammalian mitochondria, an IF1 homolog has never been detected. Here, we show that bovine mitochondrial IF2 (IF2mt) complements E. coli containing a deletion of the IF2 gene (E. coli ΔinfB). We find that IF1 is no longer essential in an IF2mt-supported E. coli ΔinfB strain. Furthermore, biochemical and molecular modeling data show that a conserved insertion of 37 amino acids in the IF2mt substitutes for the function of IF1. Deletion of this insertion from IF2mt supports E. coli for the essential function of IF2. However, in this background, IF1 remains essential. These observations provide strong evidence that a single factor (IF2mt) in mammalian mitochondria performs the functions of two eubacterial factors, IF1 and IF2.

Item Type:	Journal Article
Publication:	Molecular Cell
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	08 Mar 2010 12:38
Last Modified:	19 Sep 2010 05:56
URI:	http://eprints.iisc.ac.in/id/eprint/25928

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