Abstract
In contrast to prokaryotic elongation factor EF-Tu, which delivers aminoacyl-tRNAs to the ribosomal A-site, eukaryotic initiation factor eIF2 binds methionyl initiator transfer RNA (Met-tRNA i Met) to the P-site of the 40S ribosomal subunit. The results of directed hydroxyl radical probing experiments to map binding of Saccharomyces cerevisiae eIF2 on the ribosome and on Met-tRNA i Met revealed that eIF2γ primarily contacts the acceptor stem of Met-tRNA i Met and identified a key binding interface between domain III of eIF2γ and 18S rRNA helix h44 on the 40S subunit. Whereas the analogous domain III of EF-Tu contacts the T stem of tRNAs, biochemical analyses demonstrated that eIF2γ domain III is important for ribosome, not Met-tRNA i Met. Thus, despite their structural similarity, eIF2 and EF-Tu bind tRNAs in substantially different manners, and we propose that the tRNA-binding domain III of EF-Tu has acquired a new ribosome-binding function in eIF2γ.
Original language | English (US) |
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Pages (from-to) | 1227-1234 |
Number of pages | 8 |
Journal | Nature Structural and Molecular Biology |
Volume | 18 |
Issue number | 11 |
DOIs | |
State | Published - Nov 2011 |
Externally published | Yes |
ASJC Scopus subject areas
- Structural Biology
- Molecular Biology