FIGURE 5.

Preventing the radiation damage and raising the image contrast by heavy metal ion. (A) Overview cryo-positive-staining (cryo-PS) EM image of DNA origami in vitreous ice. (B) Magnified image of DNA origami boxed in (A). (C) Final 3D reconstruction (up) and its model with flexible fitted structure (yellow ribbon). (D) Schematic diagrams of the defined internal angles within a particle. Reproduced with permission (Lei et al., 2018). (E) and (F) show two representative images of CETP imaged by cryo-PS (the left: a raw particle with reversed contrast, the middle: noise-reduced image of the raw particles, and the right: the X-ray crystal structure), in which the secondary structure details are indicated by arrowheads. Reproduced with permission (Zhang et al., 2012b).