Fig. 1: Cryo-EM structures of the 70 S ribosome initiation complex bound to IF2-GDP and IF2-GDPCP.
From: Compact IF2 allows initiator tRNA accommodation into the P site and gates the ribosome to elongation
a Cryo-EM map of the Pseudomonas aeruginosa 70S-IC bound to compact IF2-GDP in structure I-A. The 50 S and 30 S subunits are shown in light blue and yellow, respectively. The initiator tRNA is green, mRNA is cyan, and domains of IF2 are assigned distinct colors. b Model of compact IF2-GDP in structure I-A. Relative to extended IF2 (c, d), the distal tRNA-binding domain C2 (red) collapses onto the core domains of compact IF2. c Cryo-EM map of the 70S-IC bound to extended IF2-GDPCP in structure II-A. d Model of extended IF2-GDPCP in structure II-A. The C2-domain (red) interacts with the fMet moiety of initiator tRNA bound in the p/PI state. The rotation angle of the 30 S subunit in the 70S-IC relative to the non-rotated P. aeruginosa 70 S ribosome44 is indicated under each map (a, c). The N2 sub-domain (brown) of IF2 is only visible in the rotated 70S-IC (c, d).
