title: Ab initio structure determination from prion nanocrystals at atomic resolution by MicroED.
abstract: Electrons, because of their strong interaction with matter, produce high-resolution diffraction patterns from tiny 3D crystals only a few hundred nanometers thick in a frozen-hydrated state. This discovery offers the prospect of facile structure determination of complex biological macromolecules, which cannot be coaxed to form crystals large enough for conventional crystallography or cannot easily be produced in sufficient quantities. Two potential obstacles stand in the way. The first is a phenomenon known as dynamical scattering, in which multiple scattering events scramble the recorded electron diffraction intensities so that they are no longer informative of the crystallized molecule. The second obstacle is the lack of a proven means of de novo phase determination, as is required if the molecule crystallized is insufficiently similar to one that has been previously determined. We show with four structures of the amyloid core of the Sup35 prion protein that, if the diffraction resolution is high enough, sufficiently accurate phases can be obtained by direct methods with the cryo-EM method microelectron diffraction (MicroED), just as in X-ray diffraction. The success of these four experiments dispels the concern that dynamical scattering is an obstacle to ab initio phasing by MicroED and suggests that structures of novel macromolecules can also be determined by direct methods.
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90024-1570; University of California, Los Angeles-Department of Energy Institute, University of California, Los Angeles, CA 90024-1570; Department of Biological Chemistry, University of California, Los Angeles, CA 90024-1570; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024-1570; Molecular Biology Institute, University of California, Los Angeles, CA 90024-1570.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Sawaya
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90024-1570; University of California, Los Angeles-Department of Energy Institute, University of California, Los Angeles, CA 90024-1570; Department of Biological Chemistry, University of California, Los Angeles, CA 90024-1570; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024-1570; Molecular Biology Institute, University of California, Los Angeles, CA 90024-1570.
authors.forename: Jose
authors.initials: J
authors.lastname: Rodriguez
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90024-1570; University of California, Los Angeles-Department of Energy Institute, University of California, Los Angeles, CA 90024-1570; Department of Biological Chemistry, University of California, Los Angeles, CA 90024-1570; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024-1570; Molecular Biology Institute, University of California, Los Angeles, CA 90024-1570.
authors.forename: Duilio
authors.initials: D
authors.lastname: Cascio
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90024-1570; University of California, Los Angeles-Department of Energy Institute, University of California, Los Angeles, CA 90024-1570; Department of Biological Chemistry, University of California, Los Angeles, CA 90024-1570; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024-1570; Molecular Biology Institute, University of California, Los Angeles, CA 90024-1570.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Collazo
authors.affiliation: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147.
authors.forename: Dan
authors.initials: D
authors.lastname: Shi
authors.affiliation: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147.
authors.forename: Francis E
authors.initials: FE
authors.lastname: Reyes
authors.affiliation: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147.
authors.forename: Johan
authors.identifier: 0000-0002-8936-0912
authors.initials: J
authors.lastname: Hattne
authors.affiliation: Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147 gonent@janelia.hhmi.org david@mbi.ucla.edu.
authors.forename: Tamir
authors.initials: T
authors.lastname: Gonen
authors.affiliation: Howard Hughes Medical Institute, University of California, Los Angeles, CA 90024-1570; University of California, Los Angeles-Department of Energy Institute, University of California, Los Angeles, CA 90024-1570; Department of Biological Chemistry, University of California, Los Angeles, CA 90024-1570; Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024-1570; Molecular Biology Institute, University of California, Los Angeles, CA 90024-1570; gonent@janelia.hhmi.org david@mbi.ucla.edu.
authors.forename: David S
authors.initials: DS
authors.lastname: Eisenberg
mesh_terms: D000595:Amino Acid Sequence; D000682:Amyloid / Q000737:chemistry; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D006859:Hydrogen / Q000737:chemistry; D008958:Models, Molecular; D053758:Nanoparticles / Q000737:chemistry*; D011328:Prions / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000682:Amyloid; D011328:Prions; D006859:Hydrogen
keywords: MicroED; electron diffraction; nanocrystal; phasing; prion