Compact IF2 allows initiator tRNA accommodation into the P site and gates the ribosome to elongation.

ABSTRACT: During translation initiation, initiation factor 2 (IF2) holds initiator transfer RNA (fMet-tRNA_i^fMet) in a specific orientation in the peptidyl (P) site of the ribosome. Upon subunit joining IF2 hydrolyzes GTP and, concomitant with inorganic phosphate (P_i) release, changes conformation facilitating fMet-tRNA_i^fMet accommodation into the P site and transition of the 70 S ribosome initiation complex (70S-IC) to an elongation-competent ribosome. The mechanism by which IF2 separates from initiator tRNA at the end of translation initiation remains elusive. Here, we report cryo-electron microscopy (cryo-EM) structures of the 70S-IC from Pseudomonas aeruginosa bound to compact IF2-GDP and initiator tRNA. Relative to GTP-bound IF2, rotation of

SUBMITTER: Basu RS 

PROVIDER: S-EPMC9192638 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature