Interaction of mammalian mitochondrial initiation factors IF2mt and IF3mt (2008)

Undergraduates: Kevin Elmore, Emdadul Haque

Faculty Advisor: Linda Spremulli
Department: Chemistry

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Initiation factors IF2 and IF3 aid in positioning fMet-tRNA and the mRNA start codon in their correct positions on the ribosome for the initiation of translation. Preliminary evidence gathered using surface plasmon resonance and cross-linking indicates an interaction between IF2 and IF3 for the E. coli and bovine mitochondrial systems. The Kd for binding between the mitochondrial factors is 6 ?M. Domain V of mitochondrial IF2 appears to be involved in interaction with IF3. The positioning of domain V makes it a feasible location for interaction while IF2mt positions fMet-tRNA in the ribosome. In traditional models, IF2 and IF3 do not interact during initiation, and are expected to function independently. This result may have important consequences in modeling the role of IF2 and IF3 in initiation, as well as the location of each factor on the ribosome. The data supports the idea that IF2 and IF3 are positioned close enough to make contact in the ribosome.