Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bacterial Pac Man molecule snaps at sugar

11.01.2017

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system with which they can absorb the sugar compound. They use sialic acid, for instance, to produce energy, but also to escape the eagle eyes of the immune system.


The P domain (yellow) patrols with its mouth open until it encounters a sialic acid molecule (purple). This movement was analyzed with distance measurements using the spin markers shown in blue.

© Dr. Gregor Hagelüken/Uni Bonn

To do this, they incorporate the sugar into their cell surface. Thanks to this invisibility cloak made from substances produced naturally in the body, immune cells do not notice that the bacteria are intruders.

Many bacteria are surrounded by two membranes, which cover them like a thick skin. The absorption of sialic acid through the inner membrane often takes place via molecules that are known as TRAP transporters. They are comprised of three components.

One of these – the P domain – moves freely and patrols between the two membranes. If it meets a sialic acid molecule, it grabs it and brings it to the inner membrane, where the two other components are firmly anchored. They then translocate the sugar compound into the bacteria cell.

Rapid masticatory movement

“The atomic structure of the P domain was already known,” explains Dr. Gregor Hagelüken from the Institute for Physical and Theoretical Chemistry at the University of Bonn. “Together with our collaborator Dr. Gavin Thomas from the University of York, we wanted to analyse how exactly the P domain grabs the sialic acid.

We have now been able to show that – metaphorically speaking – it lies in wait with its mouth open until it encounters a sugar molecule. At this moment, its jaws snap shut.” The P domain thus performs a rapid grabbing motion, which is somewhat reminiscent of the computer game character Pac Man.

The researchers used EPR spectroscopy in their work, a method with which the distances between parts of molecules can be measured precisely to a ten-millionth of a millimeter. In this way, they were able to understand the movement of the “Pac Man jaw”.

“To achieve this, we planted the blueprint for the P domain in harmless intestinal bacteria and grew them in a test tube,” explains Janin Glänzer, PhD student at the Institute for Physical and Theoretical Chemistry. “We then cleaned the protein in an elaborate procedure and provided it with various quantities of sialic acid.”

In order to investigate the masticatory movement, the researchers used a trick: they fitted molecular labels to the “jaw” of the P domain and then measured the precise distance between these markers. “We were able to show that the P domain can only exist in two forms: opened and closed,” says the chemist Martin Peter, who worked on this topic in his master thesis.

“We were not able to identify any stable intermediate form. Without sialic acid, all P domains are found in an open state. The more sugar we provided, the more P domains were closed.”

Hagelüken hopes that the knowledge may help to develop new active ingredients against pathogens. “We can, for instance, attempt to prevent the masticatory movement – for example, using a molecular muzzle.”

Publication: J. Glaenzer, M. Peter, G. H. Thomas, G. Hagelueken: PELDOR Spectroscopy Reveals Two Defined States of a Sialic Acid TRAP Transporter SBP in Solution, Biophysical Journal, DOI: 10.1016/j.bpj.2016.12.010

Contact:

Dr. Gregor Hagelüken
Institute for Physical and
Theoretical Chemistry
University of Bonn
Tel. +49 (0)228/733830
E-mail: hagelueken@pc.uni-bonn.de

Johannes Seiler | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-bonn.de

More articles from Life Sciences:

nachricht Cnidarians remotely control bacteria
21.09.2017 | Christian-Albrechts-Universität zu Kiel

nachricht Immune cells may heal bleeding brain after strokes
21.09.2017 | NIH/National Institute of Neurological Disorders and Stroke

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>