Structure of the native supercoiled flagellar hook as a universal joint

AbstractThe Bacterial flagellar hook is a short supercoiled tubular structure made from a helical assembly of the hook protein FlgE. The hook acts as a universal joint that connects the flagellar basal body and filament, and smoothly transmits torque generated by the rotary motor to the helical filament propeller. In peritrichously flagellated bacteria, the hook allows the filaments to form a bundle behind the cell for swimming, and for the bundle to fall apart for tumbling. Here we report a native supercoiled hook structure at 3.6 Å resolution by cryoEM single particle image analysis of the polyhook. The atomic model built into the three-dimensional (3D) density map reveals the changes in subunit conformation and intersubunit interactions that occur upon compression and extension of the 11 protofilaments during their smoke ring-like rotation. These observations reveal how the hook functions as a dynamic molecular universal joint with high bending flexibility and twisting rigidity.

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Structure of the native supercoiled flagellar hook as a universal joint

10.1101/748384 ◽

2019 ◽

Cited By ~ 1

Author(s):

Takayuki Kato ◽

Fumiaki Makino ◽

Tomoko Miyata ◽

Peter Horváth ◽

Keiichi Namba

Keyword(s):

Image Analysis ◽

Basal Body ◽

Inner Core ◽

Three Dimensional ◽

Approximate Model ◽

Atomic Model ◽

Universal Joint ◽

Supercoiled Form ◽

Smoke Ring ◽

Intersubunit Interactions

Bacteria swim in viscous liquid environments by using the flagellum1–3. The flagellum is composed of about 30 different proteins and can be roughly divided into three parts: the basal body, the hook and the filament. The basal body acts as a rotary motor powered by ion motive force across the cytoplasmic membrane as well as a protein export apparatus to construct the axial structure of the flagellum. The filament is as a helical propeller, and it is a supercoiled form of a helical tubular assembly consisting of a few tens of thousands of flagellin molecules4. The hook is a relatively short axial segment working as a universal joint connecting the basal body and the filament for smooth transmission of motor torque to the filament5,6. The structure of hook has been studied by combining X-ray crystal structure of a core fragment of hook protein FlgE and electron cryomicroscopy (cryoEM) helical image analysis of the polyhook in the straight form and has given a deep insight into the universal joint mechanism7. However, the supercoiled structure of the hook was an approximate model based on the atomic model of the straight hook without its inner core domain7 and EM observations of supercoiled polyhook by freeze-dry and Pt/Pd shadow cast8. Here we report the native supercoiled hook structure at 3.1 Å resolution by cryoEM single particle image analysis of the polyhook. The atomic model built on the three-dimensional (3D) density map show the actual changes in subunit conformation and intersubunit interactions upon compression and extension of the 11 protofilaments that occur during their smoke ring-like rotation and allow the hook to function as a dynamic molecular universal joint with high bending flexibility and twisting rigidity.

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Faculty Opinions recommendation of Three-dimensional structure of transporter associated with antigen processing (TAP) obtained by single Particle image analysis.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1003089.34205 ◽

2002 ◽

Author(s):

Tim Elliott

Keyword(s):

Image Analysis ◽

Single Particle ◽

Antigen Processing ◽

Particle Image ◽

Three Dimensional ◽

Dimensional Structure ◽

Three Dimensional Structure

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Three-dimensional Structure of Transporter Associated with Antigen Processing (TAP) Obtained by Single Particle Image Analysis

Journal of Biological Chemistry ◽

10.1074/jbc.m108435200 ◽

2001 ◽

Vol 276 (49) ◽

pp. 46054-46063 ◽

Cited By ~ 25

Author(s):

Giles Velarde ◽

Robert C. Ford ◽

Mark F. Rosenberg ◽

Simon J. Powis

Keyword(s):

Image Analysis ◽

Single Particle ◽

Antigen Processing ◽

Particle Image ◽

Three Dimensional ◽

Dimensional Structure ◽

Three Dimensional Structure

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Three-dimensional reconstruction of the dynactin complex by single-particle image analysis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.0409506102 ◽

2005 ◽

Vol 102 (10) ◽

pp. 3667-3672 ◽

Cited By ~ 18

Author(s):

J. L. Hodgkinson ◽

C. Peters ◽

S. A. Kuznetsov ◽

W. Steffen

Keyword(s):

Image Analysis ◽

Single Particle ◽

Particle Image ◽

Three Dimensional ◽

Three Dimensional Reconstruction ◽

Dimensional Reconstruction ◽

Dynactin Complex

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The three-dimensional structure of frozen-hydrated left- and right-handed forms of bacterial flagellar filaments from an identical serotype

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143110 ◽

1986 ◽

Vol 44 ◽

pp. 298-299

Author(s):

S. Trachtenberg ◽

D. J. DeRosier

Keyword(s):

Ionic Strength ◽

Basal Body ◽

Three Dimensional ◽

Dimensional Structure ◽

Protein Species ◽

Liquid Environment ◽

Bacterial Flagellum ◽

Left And Right ◽

Rotary Motor ◽

Helical Parameters

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.

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Structure of the Rotor of the Bacterial Flagellar Motor Revealed by Electron Cryomicroscopy and Single-particle Image Analysis

Journal of Molecular Biology ◽

10.1016/j.jmb.2004.01.034 ◽

2004 ◽

Vol 337 (1) ◽

pp. 105-113 ◽

Cited By ~ 109

Author(s):

Hirofumi Suzuki ◽

Koji Yonekura ◽

Keiichi Namba

Keyword(s):

Image Analysis ◽

Single Particle ◽

Particle Image ◽

Flagellar Motor ◽

Electron Cryomicroscopy ◽

Bacterial Flagellar Motor

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Point-group symmetry detection in three-dimensional charge density of biomolecules

Bioinformatics ◽

10.1093/bioinformatics/btz904 ◽

2019 ◽

Vol 36 (7) ◽

pp. 2237-2243

Author(s):

Cyril F Reboul ◽

Simon Kiesewetter ◽

Dominika Elmlund ◽

Hans Elmlund

Keyword(s):

Charge Density ◽

Single Particle ◽

Statistical Tests ◽

Point Group ◽

Three Dimensional ◽

Group Symmetry ◽

Point Group Symmetry ◽

Density Maps ◽

Point Groups ◽

Density Map

Abstract Motivation No rigorous statistical tests for detecting point-group symmetry in three-dimensional (3D) charge density maps obtained by electron microscopy (EM) and related techniques have been developed. Results We propose a method for determining the point-group symmetry of 3D charge density maps obtained by EM and related techniques. Our ab initio algorithm does not depend on atomic coordinates but utilizes the density map directly. We validate the approach for a range of publicly available single-particle cryo-EM datasets. In straightforward cases, our method enables fully automated single-particle 3D reconstruction without having to input an arbitrarily selected point-group symmetry. When pseudo-symmetry is present, our method provides statistics quantifying the degree to which the 3D density agrees with the different point-groups tested. Availability and implementation The software is freely available at https://github.com/hael/SIMPLE3.0.

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