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Article Dans Une Revue Nature Communications Année : 2016

Cryo-EM study of start codon selection during archaeal translation initiation

Résumé

Eukaryotic and archaeal translation initiation complexes have a common structural core comprising e/aIF1, e/aIF1A, the ternary complex (TC, e/aIF2-GTP-Met-tRNAi(Met)) and mRNA bound to the small ribosomal subunit. e/aIF2 plays a crucial role in this process but how this factor controls start codon selection remains unclear. Here, we present cryo-EM structures of the full archaeal 30S initiation complex showing two conformational states of the TC. In the first state, the TC is bound to the ribosome in a relaxed conformation with the tRNA oriented out of the P site. In the second state, the tRNA is accommodated within the peptidyl (P) site and the TC becomes constrained. This constraint is compensated by codon/anticodon base pairing, whereas in the absence of a start codon, aIF2 contributes to swing out the tRNA. This spring force concept highlights a mechanism of codon/anticodon probing by the initiator tRNA directly assisted by aIF2.

Dates et versions

hal-03690155 , version 1 (07-06-2022)

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Pierre Damien Coureux, Christine Lazennec-Schurdevin, Aurianne Monestier, Eric Larquet, Lionel Cladiere, et al.. Cryo-EM study of start codon selection during archaeal translation initiation. Nature Communications, 2016, 7, ⟨10.1038/ncomms13366⟩. ⟨hal-03690155⟩
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