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Title | Conformational transition of initiation factor 2 from the GTP- to GDP-bound state visualized on the ribosome. |
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Journal, issue, pages | Nat Struct Mol Biol, Vol. 12, Issue 12, Page 1145-1149, Year 2005 |
Publish date | Nov 13, 2005 |
Authors | Alexander G Myasnikov / Stefano Marzi / Angelita Simonetti / Anna Maria Giuliodori / Claudio O Gualerzi / Gulnara Yusupova / Marat Yusupov / Bruno P Klaholz / |
PubMed Abstract | Initiation of protein synthesis is a universally conserved event that requires initiation factors IF1, IF2 and IF3 in prokaryotes. IF2 is a GTPase essential for binding initiator transfer RNA to the ...Initiation of protein synthesis is a universally conserved event that requires initiation factors IF1, IF2 and IF3 in prokaryotes. IF2 is a GTPase essential for binding initiator transfer RNA to the 30S ribosomal subunit and recruiting the 50S subunit into the 70S initiation complex. We present two cryo-EM structures of the assembled 70S initiation complex comprising mRNA, fMet-tRNA(fMet) and IF2 with either a non-hydrolyzable GTP analog or GDP. Transition from the GTP-bound to the GDP-bound state involves substantial conformational changes of IF2 and of the entire ribosome. In the GTP analog-bound state, IF2 interacts mostly with the 30S subunit and extends to the initiator tRNA in the peptidyl (P) site, whereas in the GDP-bound state IF2 steps back and adopts a 'ready-to-leave' conformation. Our data also provide insights into the molecular mechanism guiding release of IF1 and IF3. |
External links | Nat Struct Mol Biol / PubMed:16284619 |
Methods | EM (single particle) |
Resolution | 11.0 - 11.5 Å |
Structure data | EMDB-1172: EMDB-1173: |
Source |
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