title: Structure determination of tubular crystals of membrane proteins. II. Averaging of tubular crystals of different helical classes.
abstract: 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.
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yonekura
authors.forename: C
authors.initials: C
authors.lastname: Toyoshima
mesh_terms: D000252:Calcium-Transporting ATPases / Q000737:chemistry* / Q000648:ultrastructure; D003461:Crystallography / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008854:Microscopy, Electron; D008962:Models, Theoretical; D017433:Protein Structure, Secondary; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D012985:Software Design
chemical_list: D000252:Calcium-Transporting ATPases