title: Single particle refinement in electron crystallography: a pilot study.
abstract: Electron crystallography can be used to determine the structures of membrane proteins at near-atomic resolution in some cases. However, most electron crystallography projects remain at a resolution around 10A. This might be partly due to lack of flatness of many two-dimensional crystals. We have investigated this problem and suggest single particle processing of locally averaged unit cells to improve the quality and possibly the resolution of three-dimensional maps. Applying this method to the secondary transporter melibiose permease we have calculated a three-dimensional map that is clearer and easier to interpret than the map derived using purely electron-crystallographic methods.
authors.affiliation: Royal Institute of Technology, School of Technology and Health, Sweden. Philip.Koeck@csb.ki.se
authors.forename: Philip J B
authors.initials: PJ
authors.lastname: Koeck
authors.forename: Pasi
authors.initials: P
authors.lastname: Purhonen
authors.forename: Ronny
authors.initials: R
authors.lastname: Alvang
authors.forename: Björn
authors.initials: B
authors.lastname: Grundberg
authors.forename: Hans
authors.initials: H
authors.lastname: Hebert
mesh_terms: D003198:Computer Simulation; D003460:Crystallization; D003461:Crystallography / Q000379:methods*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000648:ultrastructure; D005583:Fourier Analysis; D021621:Imaging, Three-Dimensional / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D008958:Models, Molecular; D010865:Pilot Projects; D011487:Protein Conformation; D027981:Symporters / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D029968:Escherichia coli Proteins; D027981:Symporters; C021548:melibiose permease