title: Robust filtering and particle picking in micrograph images towards 3D reconstruction of purified proteins with cryo-electron microscopy.
abstract: In order to make a high resolution model of macromolecular structures from cryo-electron microscope (cryo-EM) raw images one has to be precise at every processing step from particle picking to 3D image reconstruction. In this paper we propose a collection of novel methods for filtering cryo-EM images and for automatic picking of particles. These methods have been developed for two cases: (1) when particles can be identified and (2) when particle are not distinguishable. The advantages of these methods are demonstrated in standard purified protein samples and to generalize them we do not use any ad hoc presumption of the geometry of the particle projections. We have also suggested a filtering method to increase the signal-to-noise (S/N) ratio which has proved to be useful for other levels of reconstruction, i.e., finding orientations and 3D model reconstruction.
authors.affiliation: Laboratory of Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FIN-02015 HUT Helsinki, Finland. vibhor.kumar@hut.fi
authors.forename: Vibhor
authors.initials: V
authors.lastname: Kumar
authors.forename: Jukka
authors.initials: J
authors.lastname: Heikkonen
authors.forename: Peter
authors.initials: P
authors.lastname: Engelhardt
authors.forename: Kimmo
authors.initials: K
authors.lastname: Kaski
mesh_terms: D000465:Algorithms; D000818:Animals; D025622:Bacteriophage PRD1 / Q000737:chemistry / Q000648:ultrastructure; D020285:Cryoelectron Microscopy / Q000379:methods*; D001330:Electronic Data Processing / Q000379:methods; D006433:Hemocyanins / Q000737:chemistry / Q000648:ultrastructure; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional; D015233:Models, Statistical; D008974:Mollusca; D010316:Particle Size; D010363:Pattern Recognition, Automated; D011336:Probability; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry / Q000648:ultrastructure*; D029262:Puumala virus / Q000737:chemistry; D012985:Software Design; D014764:Viral Proteins / Q000737:chemistry / Q000648:ultrastructure
chemical_list: D011506:Proteins; D014764:Viral Proteins; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin