Cryo-EM Particle Picking
Cryo-Electron Microscopy (cryo-EM) is a technique
for getting 3D structures of biological molecules from
an electron microscope.
Single-particle cryo-EM gathers many images of the same
particle (molecule or molecular complex) in various
orientations, and then uses something like computed tomography
to reconstruct the 3D structure.
Cryo-EM routinely determines structures
to about 15 Angstrom resolution, but with enough
images (100,000 or more) resolutions of 7 or 8 Angstroms
should be attainable.
So a key problem is automatically finding
the particle images inside the micrographs.
We are working with micrographs from the
Scripps Research Institute's
Center
for Integrative Molecular Biosciences.
To pick particles, we use a probabilistic model of cryo-EM imaging
and a coarse "3D template" reconstructed
from a few hundred hand-picked images.
Here are some preliminary results on p97 ATPase.
This page updated August 2002 / bern@parc.com