title: Ab initio structure determination from electron microscopic images of single molecules coexisting in different functional states.
abstract: We have developed methods for ab initio three-dimensional (3D) structure determination from projection images of randomly oriented single molecules coexisting in multiple functional states, to aid the study of complex samples of macromolecules and nanoparticles by electron microscopy (EM). New algorithms for the determination of relative 3D orientations and conformational state assignment of single-molecule projection images are combined with well-established techniques for alignment and statistical image analysis. We describe how the methodology arrives at homogeneous groups of images aligned in 3D and discuss application to experimental EM data sets of the Escherichia coli ribosome and yeast RNA polymerase II.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institutet, Novum, SE-141 86 Huddinge, Sweden.
authors.forename: Dominika
authors.initials: D
authors.lastname: Elmlund
authors.forename: Ralph
authors.initials: R
authors.lastname: Davis
authors.forename: Hans
authors.initials: H
authors.lastname: Elmlund
mesh_terms: D000465:Algorithms; D020285:Cryoelectron Microscopy / Q000379:methods*; D004926:Escherichia coli; D005583:Fourier Analysis; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D012319:RNA Polymerase II / Q000737:chemistry*; D012270:Ribosomes / Q000648:ultrastructure*; D015003:Yeasts
chemical_list: D012319:RNA Polymerase II