Figure 1. Structures and electron density maps of the ribosome‐bound aminoacyl‐ and dipeptidyl‐tRNA analogs.

The refined models of four crystal structures of the ribosome bound to aminoacyl‐ or peptidyl‐tRNA analogs are displayed in their respective unbiased electron density F_o‐F_c maps (contoured at 2.5 σ). The maps were calculated using phases produced by rigid body refinement of the ligand‐free test structure put into the F_o dataset.

• A, B
  A‐site‐bound substrates ACC‐puromycin (A) and ACCA‐Pro (B).
• C, D
  P‐site‐bound substrates ACCA‐Leu‐Phe (C) and ACCA‐Pro‐Pro (D).

Data information: The insets in each panel indicate position of a ligand relative to the A‐site (in yellow) and P‐site (in green) of the ribosome; the actual binding site of each ligand is highlighted in red.