title: Non-rigid image registration to reduce beam-induced blurring of cryo-electron microscopy images.
abstract: The typical dose used to record cryo-electron microscopy images from vitrified biological specimens is so high that radiation-induced structural alterations are bound to occur during data acquisition. Integration of all scattered electrons into one image can lead to significant blurring, particularly if the data are collected from an unsupported thin layer of ice suspended over the holes of a support film. Here, the dose has been fractioned and exposure series have been acquired in order to study beam-induced specimen movements under low dose conditions, prior to bubbling. Gold particles were added to the protein sample as fiducial markers. These were automatically localized and tracked throughout the exposure series and showed correlated motions within small patches, with larger amplitudes of motion vectors at the start of a series compared with the end of each series. A non-rigid scheme was used to register all images within each exposure series, using natural neighbor interpolation with the gold particles as anchor points. The procedure increases the contrast and resolution of the examined macromolecules.
authors.affiliation: Department of Molecular Cell Biology, Leiden University Medical Center, PO Box 9600, 2300RC Leiden, The Netherlands.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Karimi Nejadasl
authors.forename: Manikandan
authors.initials: M
authors.lastname: Karuppasamy
authors.forename: Emily R
authors.initials: ER
authors.lastname: Newman
authors.forename: John E
authors.initials: JE
authors.lastname: McGeehan
authors.forename: Raimond B G
authors.initials: RB
authors.lastname: Ravelli
mesh_terms: D020285:Cryoelectron Microscopy / Q000379:methods*; D006046:Gold; D006657:Histones / Q000737:chemistry / Q000528:radiation effects; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D046911:Macromolecular Substances / Q000528:radiation effects*; D009068:Movement; D056490:Nucleosome Assembly Protein 1 / Q000737:chemistry / Q000528:radiation effects
chemical_list: D006657:Histones; D046911:Macromolecular Substances; D056490:Nucleosome Assembly Protein 1; D006046:Gold