Atoms of Apoferritin
At a miraculous 1.22 Å resolution, the electron microscopy map of
mouse apoferritin (right,
can be mistaken for an atomic model (left,
with each atom standing out.
The map from Nakane et al. (2020 Nature 587:152-156)
shows glimpses of the lightest atoms, hydrogen, directly revealing the
Ferritin stores iron, as many as 4500 ions (Fe3+), as crystallites
within its shell of 24 proteins. Apoferritin, ferritin without its iron cargo,
has rock-like stability, making it ideal for divining the limits of
electron microscope resolution.
The images were made with UCSF ChimeraX,
using ambient-occlusion lighting,
coloring to delineate trimeric subunits within the dodecahedral shell,
and curved helix tubes.
Best wishes for a happy and healthy 2021!
Conrad, Greg, Elaine, Tristan, Tom, Scooter, Eric and Tom