Featured Research

from universities, journals, and other organizations

How bacteria make syringes: Scientists reconstruct a bacterial transport channel in a test tube

Date:
June 14, 2010
Source:
Max-Planck-Gesellschaft
Summary:
For a successful infection, bacteria must outwit the immune system of the host. To this aim, they deliver so-called virulence factors through a transport channel located in the bacterial membrane. In some bacteria this transport channel is formed like a syringe, enabling them to inject virulence factors directly into the host cell.

Shigella flexneri, the causative agent of dysentery (orange), establishes contact with a human host cell (blue). The bar corresponds to a micrometer or a thousandth millimeter, respectively.
Credit: Volker Brinkmann, Diane Schad, and Michael Kolbe

For a successful infection, bacteria must outwit the immune system of the host. To this aim, they deliver so-called virulence factors through a transport channel located in the bacterial membrane. In some bacteria this transport channel is formed like a syringe, enabling them to inject virulence factors directly into the host cell.

Related Articles


Scientists from the Max Planck Society and the Federal Institute for Materials Research and Testing have now succeeded for the first time in elucidating basic principles of the assembly of this transport channel. This is an important starting point for the development of new drugs that might interfere considerably earlier than antibiotics in the course of infection. The research is published in Nature Structural & Molecular Biology.

Every day the human organism is confronted with a huge variety of pathogens. Most of them are fended off by our immune system. To execute a successful infection, bacteria must therefore manipulate the host to ensure their survival. They secrete virulence factors through a transport channel located in the bacterial membrane. Some bacteria, such as the causative agents of dysentery, food poisoning, typhoid fever, and pest, have developed a specialized transport mechanism called the Type three secretion system. Electron microscopy reveals that this structure is formed like a syringe: the base of the syringe is imbedded in the bacterial membrane and the needle protrudes out of the bacteria. With this apparatus bacteria can inject virulence factors directly into the host cell.

So far, little has been known about how bacteria build this nano-syringe. Scientists from the Max Planck Institute for Infection Biology in Berlin, the Max Planck Institute for Biophysical Chemistry in Göttingen, and the Federal Institute for Materials Research and Testing have now succeeded in elucidating fundamental principles of the needle assembly. This was made possible by reconstitution experiments which allowed them to study the assembly of proteins into a needle in the test tube.

The close observation of these events revealed how the proteins are assembled into a syringe: the bacterium synthesizes the proteins in the cell interior, transports them through the syringe to the outside, and stacks them one after the other onto the tip of the growing needle. The scientists could also show that the proteins change their three-dimensional structure during the assembly process. They were able to pinpoint the exact structural changes down to the single amino acid level. These results open new perspectives in the development of medicines that might interfere in the course of infection much earlier than antibiotics. These so-called anti-infectives could inhibit the assembly of the needle and the injection of virulence factors into the host cell. This would be a major advantage over antibiotics, which have to travel through the membrane into the bacteria to be able to kill it. Furthermore, antibiotics cannot distinguish between good and evil, i.e. disease-causing, bacteria, often leading to unwanted side effects. Lastly, the use of anti-infectives would circumvent the problem of antibiotic resistance development.

The change of the three-dimensional structure of the proteins during the needle assembly was analyzed by X-ray structural experiments at BESSY in Berlin and ESRF in Grenoble and NMR-spectroscopic experiments based on radio waves at the Max Planck Institute for Biophysical Chemistry. The scientists compared the three-dimensional structure of the needle protein before and after the needle assembly.


Story Source:

The above story is based on materials provided by Max-Planck-Gesellschaft. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ömer Poyraz, Holger Schmidt, Karsten Seidel, Friedmar Delissen, Christian Ader, Hezi Tenenboim, Christian Goosmann, Britta Laube, Andreas F Thünemann, Arturo Zychlinsky, Marc Baldus, Adam Lange, Christian Griesinger, Michael Kolbe. Protein refolding is required for assembly of the type three secretion needle. Nature Structural & Molecular Biology, 2010; DOI: 10.1038/nsmb.1822

Cite This Page:

Max-Planck-Gesellschaft. "How bacteria make syringes: Scientists reconstruct a bacterial transport channel in a test tube." ScienceDaily. ScienceDaily, 14 June 2010. <www.sciencedaily.com/releases/2010/06/100613181243.htm>.
Max-Planck-Gesellschaft. (2010, June 14). How bacteria make syringes: Scientists reconstruct a bacterial transport channel in a test tube. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2010/06/100613181243.htm
Max-Planck-Gesellschaft. "How bacteria make syringes: Scientists reconstruct a bacterial transport channel in a test tube." ScienceDaily. www.sciencedaily.com/releases/2010/06/100613181243.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Stray Dog Follows Adventure Racing Team for 6-Day Endurance Race

Buzz60 (Nov. 24, 2014) — A Swedish Adventure racing team travels to try and win a world title, but comes home with something way better: a stray dog that joined the team for much of the grueling 430-mile race. Jen Markham has the story. Video provided by Buzz60
Powered by NewsLook.com
Deadly Japanese Pufferfish Discovered in Crimean Waters

Deadly Japanese Pufferfish Discovered in Crimean Waters

Reuters - Light News Video Online (Nov. 24, 2014) — The capture of deadly Japanese pufferfish in the waters of Crimea is causing concern for fishermen and scientists alike. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com
Terrifying Black Seadevil Fish Captured on First-of-Its Kind Video

Terrifying Black Seadevil Fish Captured on First-of-Its Kind Video

Buzz60 (Nov. 24, 2014) — An aquarium captures a first-of-its kind video of a notoriously camera-shy fish that’s also not so camera-friendly. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Red Panda Cubs Explore the Bratislava Zoo

Red Panda Cubs Explore the Bratislava Zoo

AFP (Nov. 24, 2014) — Four-month old Red Panda twins Pim and Pam still rely on their mother for breast milk at the Bratislava Zoo in Slovakia, but the precocious cubs have begun to branch out to solid foods, as well. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins