Summary information and primary citation
- PDB-id
-
6swd;
DSSR-derived features in text and
JSON formats; DNAproDB
- Class
- ribosome
- Method
- cryo-EM (3.2 Å)
- Summary
- Ic2 body model of cryo-EM structure of a full archaeal
ribosomal translation initiation complex devoid of aif1 in
p. abyssi
- Reference
-
Coureux PD, Lazennec-Schurdevin C, Bourcier S, Mechulam
Y, Schmitt E (2020): "Cryo-EM
study of an archaeal 30S initiation complex gives
insights into evolution of translation initiation."
Commun Biol, 3, 58. doi:
10.1038/s42003-020-0780-0.
- Abstract
- Archaeal translation initiation occurs within a
macromolecular complex containing the small ribosomal
subunit (30S) bound to mRNA, initiation factors aIF1, aIF1A
and the ternary complex
aIF2:GDPNP:Met-tRNA<sub>i</sub><sub>Met</sub>.
Here, we determine the cryo-EM structure of a
30S:mRNA:aIF1A:aIF2:GTP:Met-tRNA<sub>i</sub><sub>Met</sub>
complex from Pyrococcus abyssi at 3.2 Å resolution. It
highlights archaeal features in ribosomal proteins and rRNA
modifications. We find an aS21 protein, at the location of
eS21 in eukaryotic ribosomes. Moreover, we identify an
N-terminal extension of archaeal eL41 contacting the P
site. We characterize 34
N<sub>4</sub>-acetylcytidines distributed
throughout 16S rRNA, likely contributing to
hyperthermostability. Without aIF1, the 30S head is
stabilized and initiator tRNA is tightly bound to the P
site. A network of interactions involving tRNA, mRNA, rRNA
modified nucleotides and C-terminal tails of uS9, uS13 and
uS19 is observed. Universal features and domain-specific
idiosyncrasies of translation initiation are discussed in
light of ribosomal structures from representatives of each
domain of life.
