Cryo-EM study of an archaeal 30S initiation complex gives insights into evolution of translation initiation.
Commun Biol
; 3(1): 58, 2020 02 06.
Article
in En
| MEDLINE
| ID: mdl-32029867
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 aIF2GDPNPMet-tRNAiMet. Here, we determine the cryo-EM structure of a 30SmRNAaIF1AaIF2GTPMet-tRNAiMet 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 N4-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.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Peptide Chain Initiation, Translational
/
Archaea
/
Cryoelectron Microscopy
/
Biological Evolution
/
Ribosome Subunits, Small, Archaeal
Type of study:
Prognostic_studies
Language:
En
Journal:
Commun Biol
Year:
2020
Document type:
Article
Affiliation country:
France