TY - JOUR
T1 - eIF5B and eIF1A reorient initiator tRNA to allow ribosomal subunit joining
AU - Lapointe, Christopher P.
AU - Grosely, Rosslyn
AU - Sokabe, Masaaki
AU - Alvarado, Carlos
AU - Wang, Jinfan
AU - Montabana, Elizabeth
AU - Villa, Nancy
AU - Shin, Byung Sik
AU - Dever, Thomas E.
AU - Fraser, Christopher S.
AU - Fernández, Israel S.
AU - Puglisi, Joseph D.
N1 - Publisher Copyright:
© 2022, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2022/7/7
Y1 - 2022/7/7
N2 - Translation initiation defines the identity and quantity of a synthesized protein. The process is dysregulated in many human diseases1,2. A key commitment step is when the ribosomal subunits join at a translation start site on a messenger RNA to form a functional ribosome. Here, we combined single-molecule spectroscopy and structural methods using an in vitro reconstituted system to examine how the human ribosomal subunits join. Single-molecule fluorescence revealed when the universally conserved eukaryotic initiation factors eIF1A and eIF5B associate with and depart from initiation complexes. Guided by single-molecule dynamics, we visualized initiation complexes that contained both eIF1A and eIF5B using single-particle cryo-electron microscopy. The resulting structure revealed how eukaryote-specific contacts between the two proteins remodel the initiation complex to orient the initiator aminoacyl-tRNA in a conformation compatible with ribosomal subunit joining. Collectively, our findings provide a quantitative and architectural framework for the molecular choreography orchestrated by eIF1A and eIF5B during translation initiation in humans.
AB - Translation initiation defines the identity and quantity of a synthesized protein. The process is dysregulated in many human diseases1,2. A key commitment step is when the ribosomal subunits join at a translation start site on a messenger RNA to form a functional ribosome. Here, we combined single-molecule spectroscopy and structural methods using an in vitro reconstituted system to examine how the human ribosomal subunits join. Single-molecule fluorescence revealed when the universally conserved eukaryotic initiation factors eIF1A and eIF5B associate with and depart from initiation complexes. Guided by single-molecule dynamics, we visualized initiation complexes that contained both eIF1A and eIF5B using single-particle cryo-electron microscopy. The resulting structure revealed how eukaryote-specific contacts between the two proteins remodel the initiation complex to orient the initiator aminoacyl-tRNA in a conformation compatible with ribosomal subunit joining. Collectively, our findings provide a quantitative and architectural framework for the molecular choreography orchestrated by eIF1A and eIF5B during translation initiation in humans.
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U2 - 10.1038/s41586-022-04858-z
DO - 10.1038/s41586-022-04858-z
M3 - Article
C2 - 35732735
AN - SCOPUS:85132344865
SN - 0028-0836
VL - 607
SP - 185
EP - 190
JO - Nature
JF - Nature
IS - 7917
ER -