A strategy for electron tomographic data collection and crystallographic reconstruction of biological bundles.
Structures of highly ordered biological bundles have unique features which call for special experimental and computational methods in electron cryomicroscopy. They can be considered as three-dimensional quasi-crystals and reconstructed using a crystallographic approach. However, they are neither "infinitely" large with respect to the borders of the bundle, nor are they a single unit cell in thickness along the viewing direction. Also, because of their shape, bundles do not generally have a preferred azimuthal orientation, which poses challenges for orientation estimation and refinement. We developed a strategy for recording and processing electron cryomicroscopic images that differs from classical two-dimensional crystalline reconstruction techniques. These developments allowed us to merge data from tomographic tilt series of ice-embedded acrosomal bundles. The goal is to determine accurately amplitudes and phases at the diffraction maxima in terms of hkl indices, and compute a three-dimensional map from the diffraction data.
Sherman
M B
MB
National Center for Macromolecular Imaging, Baylor College of Medicine, Houston, Texas 77030, USA.
Jakana
J
J
Sun
S
S
Matsudaira
P
P
Chiu
W
W
Schmid
M F
MF
D000177:Acrosome / Q000648:ultrastructure*; D000818:Animals; D018360:Crystallography, X-Ray / Q000379:methods; D005615:Freezing; D006737:Horseshoe Crabs; D007091:Image Processing, Computer-Assisted; D008297:Male; D008854:Microscopy, Electron / Q000379:methods*; D008961:Models, Structural; D013094:Spermatozoa / Q000648:ultrastructure*; D014054:Tomography