Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

3D molecular syringes - Scientists solve structure of infection tool used by Yersinia

31.07.2013
Abdominal pain, fever, diarrhoea – these symptoms could point to an infection with the bacterium Yersinia.

The bacterium’s pathogenic potential is based on a syringe-like injection apparatus called injectisome. For the first time, an international team of researchers including scientists at the Helmholtz Centre for Infection Research (HZI) in Braunschweig, Germany, has unraveled this molecular syringe’s spatial conformation.


Electron microscope image of a bacterial cell: injection apparatuses (shown in red) stick out from the cell and extend across the cell wall (shown here in yellow and blue). University of Basel / Mikhail Kudryashev

The researchers were able to demonstrate that the length of Yersinia’s injectisome’s basal body, which crosses the bacterial cell wall, is adjustable – very likely an adaptation to physical stress.

The rod-shaped bacterium Yersinia enterocolitica, which is transmitted through contaminated food, causes gastrointestinal diseases. In Germany alone, several thousand cases are reported annually. Yersinia uses a rather sophisticated tool – its injection apparatus – to infect humans. Not only does the apparatus look like a syringe, it actually serves a similar purpose.

A molecular “needle”, which sticks out from the bacterium’s surface, extends across the bacterial membranes to the host cell. It is through this needle that the bacterium “injects” substances that facilitate infection of the host. Now, for the first time, an interdisciplinary team of HZI scientists together with their colleagues at the Biozentrum of the University of Basel and at the Ecole Polytechnique Fédérale de Lausanne in Switzerland, has presented the structure of Yersinia enterocolitica‘s injectisome in high-resolution and 3D. They published their results in the digital scientific magazine eLife.

Their innovative approach has yielded surprising results. Previous studies had been concerned with isolating the molecular syringe from the bacterium and studying it under the electron microscope. “We, however, actually studied the injectisome in situ, in other words, on the bacterial surface, right where it normally occurs,” explains Prof. Henning Stahlberg, University of Basel. To this end, the researchers cooled the bacteria to minus 193 degrees Celsius and used cryo-electron microscopy to take pictures of the syringe from various angles. They then computed a spatial structure from a set of two-dimensional images – a highly effective method for examining large molecular complexes. The syringe, which consists of some 30 different proteins, definitely falls into that category.

When comparing over 2000 single syringes from over 300 bacteria, the researchers made a surprising discovery: “There is a range of different lengths of each injection apparatus’ base – in some cases, it’s on the order of ten nanometers, or ten millionth of a millimeter. It can be stretched or compressed – just like a spring,” explains Dr. Stefan Schmelz of the HZI, one of the study’s first authors. As much as we consider such dimensions to be miniscule – to a bacterium, which itself is but a hundred times that size, they are substantial. “Bacteria are exposed to considerable forces, be it during contact with other cells or upon changes in environmental salinity,” explains Prof. Dirk Heinz, the HZI’s scientific director and former head of the HZI Department of Molecular Structural Biology. “If the injectisomes were rigidly constructed, bacteria would most likely be unable to resist these forces. Their cell walls would simply rupture.”

Insights into the structure of Yersinia’s attack tool offer clues as to ways in which the molecular syringe may be therapeutically inhibited. Without this apparatus, the bacteria are practically harmless. “Also other pathogenic bacteria make use of this principle during infection, for example Salmonella that cause food poisoning,” confirms Dr. Mikhail Kudryashev, another of the study’s primary authors and a researcher at the University of Basel. The team was already able to document this same flexibility in Shigella, the causative agent behind bacillary dysentery. The “molecular building kit,” as Schmelz calls it, is highly similar, suggesting that insights from this current study can potentially also be applied to other pathogenic bacteria.

Original publication:

Mikhail Kudryashev*, Marco Stenta*, Stefan Schmelz*, Marlise Amstutz*, Ulrich Wiesand*, Daniel Castaño-Díez, Matteo T Degiacomi, Stefan Münnich, Christopher KE Bleck, Julia Kowal, Andreas Diepold, Dirk W Heinz, Matteo Dal Peraro, Guy R Cornelis, Henning Stahlberg
*These authors have contributed equally to the study.
In situ structural analysis of the Yersinia enterocolitica injectisome
eLife, 2013, DOI: http://dx.doi.org/10.7554/elife.00792
The Department „Molecular Structural Biology” investigates the spatial structure and function of individual molecules. They utilize modern technologies such as x-ray structure analysis, nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry. Their focus is on both biomacromolecules as well as low molecular natural substances.
The Helmholtz Centre for Infection Research (HZI)
Scientists at the Helmholtz Centre for Infection Research in Braunschweig, Germany, are engaged in the study of different mechanisms of infection and of the body’s response to infection. Helping to improve the scientific community’s understanding of a given bacterium’s or virus’ pathogenicity is key to developing effective new treatments and vaccines.

Dr. Birgit Manno | Helmholtz-Zentrum
Further information:
http://www.helmholtz-hzi.de
http://www.helmholtz-hzi.de/en/news_events/news/view/article/complete/3d_molecular_syringes/

More articles from Life Sciences:

nachricht A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden

nachricht Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: It’s All in the Mix: Jülich Researchers are Developing Fast-Charging Solid-State Batteries

There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.

The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...

Im Focus: Color effects from transparent 3D-printed nanostructures

New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference

Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...

Im Focus: Unraveling the nature of 'whistlers' from space in the lab

A new study sheds light on how ultralow frequency radio waves and plasmas interact

Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...

Im Focus: New interactive machine learning tool makes car designs more aerodynamic

Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.

When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...

Im Focus: Robots as 'pump attendants': TU Graz develops robot-controlled rapid charging system for e-vehicles

Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.

Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

LaserForum 2018 deals with 3D production of components

17.08.2018 | Event News

Within reach of the Universe

08.08.2018 | Event News

A journey through the history of microscopy – new exhibition opens at the MDC

27.07.2018 | Event News

 
Latest News

Quantum bugs, meet your new swatter

20.08.2018 | Information Technology

A novel synthetic antibody enables conditional “protein knockdown” in vertebrates

20.08.2018 | Life Sciences

Metamolds: Molding a mold

20.08.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>