Figure 1.

Structural and physical differences between encapsulin and ferritin protein cages and their crystalline assembly investigated via small-angle X-ray scattering. Left panels: The T. maritima encapsulin container has an outer diameter of 24 nm, icosahedral symmetry, and a negative surface charge, Enc^(neg). On the other hand, human ferritin has an outer diameter of 12 nm and octahedral symmetry. Moreover, the ferritin variant used here features a positive surface charge, Ftn^(pos). The surface charge is coded from red to blue from −5 to 5 kT/e. The assembly of the two cages forms the crystalline sample, composed of several crystals (optical microscopy image, scale bar equals 100 μm, unit cell given below the image), and it was investigated via SAXS (right panel). The correlation between experimental and theoretical q values is shown in the inset.