A set of programs has been developed for averaging the data from tubular crystals belonging to different helical classes. This was done either by (i) cutting out molecules constituting a unit cell from density maps, and aligning and averaging them in real space; (ii) transforming the densities in a unit cell to layer-line data according to a (possibly artificial) helical symmetry, aligning and averaging them in reciprocal space. These methods were applied to tubular crystals of Ca2+-ATPase. Either method worked well and substantially improved the data quality. Transforming the reconstructed images to the layer-line data has many advantages and is essential for fully exploiting the power of averaging. Copyright (C) 2000 Elsevier Science B.V.
- Cryo-electron microscopy
- Real-space averaging
- Tubular crystal
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics