Fig. 6: Cryo-EM structure of PCR-P2.
From: Atomic models of the Toxoplasma cell invasion machinery
a, Representative cryo-EM image of a conoid sample after sonication and protease treatment, showing a PCR dislodged from the conoid. Overlapping boxes (yellow rectangles) were used to extract the ring segments. b, Selected 2D class averages of ring particles showing different views. c, A hypothetical structure of a complete ring, generated by extending the single-particle structure (red dashed rectangle) using the measured angle between two consecutive repeating units. A slight misalignment was observed at the rejoining point (red arrow). Viewing angles for d and e are indicated. d,e, Top view (d) and bottom view (e) of the atomic model of the PCR-P2 containing ~3 repeating units, with component proteins shown in distinct colors. f, Atomic model of the two copies of PCR4/5 heterodimers located at the core of the PCR-P2. g, Atomic model of the two SEC23/24 heterodimers located at the inner rim of the PCR-P2. h, Atomic model of MyoL interacting with three potential myosin light chain subunits (CAM1, CAM4 and MLC4).
