A strategy for electron tomographic data collection and crystallographic reconstruction of biological bundles

J Struct Biol. 1997 Dec;120(3):245-56. doi: 10.1006/jsbi.1997.3916.

Abstract

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.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acrosome / ultrastructure*
  • Animals
  • Crystallography, X-Ray / methods
  • Freezing
  • Horseshoe Crabs
  • Image Processing, Computer-Assisted*
  • Male
  • Microscopy, Electron / methods*
  • Models, Structural
  • Spermatozoa / ultrastructure*
  • Tomography