Figure 3.

Micrographs of a single three-dimensional lysozyme crystal (200 × 500 × 1400 nm) in a thin layer of vitreous ice across a hole in the Lacey carbon EM grid at (a) +20° tilt angle and (b) +50° tilt angle. Diffraction data were acquired with a 2.0 µm diameter parallel beam in microprobe mode, indicated by a circle in (a). During data collection only the tip of the crystal was kept in the central beam to limit noise from the carbon support. The width of the crystal at both tilt angles was used to derive its dimensions; the length was measured from the tip of the crystal to the edge of the carbon and was the maximum size of the crystal within the central beam at any point during rotation.