Supplementary Figure 2: Raw cryo-EM data and classification of the reconstituted 40S–ABCE1 complex.
From: Structure of the 40S–ABCE1 post-splitting complex in ribosome recycling and translation initiation
a, Representative micrograph showing 40S–ABCE1 particles. b, Representative 2D classes predominantly showing various side views of the 40S subunits. c, 3D classification scheme. After 2D classification and removal of non-ribosomal particles, the dataset was refined and subjected to 3D classification in RELION-2. The dataset was initially classified into four classes: class 1 and 2 contained poorly resolved and distorted 40S ribosomes whereas Class 3 and 4 showed well-resolved 40S ribosomes with a strong ABCE1 density. These classes were joined for a second round of 3D classification (five classes) using a mask excluding the highly flexible 40S head. Four out of five classes showed either a strong distortion which is likely a result of orientation bias or poor alignment and were discarded. The best resolved class 1 showed a strong ABCE1 density and a well resolved 40S body and was used for the refinement yielding a map at 3.9 Å resolution.
