Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stuck on you: scientists lay bare secrets of bacterial attachment proteins

01.09.2004


An unprecedented picture of how bacteria latch on to human cells has been published by UK, French and US scientists. They have produced a finely detailed model of one of the tools used by some of the nastiest varieties of the stomach bug, Escherichia coli, to stick to and gain entry to host cells.



Led by senior author Dr Stephen Matthews, Reader in Chemical and Structural Biology at Imperial College London, the research is published in the latest issue of the journal Molecular Cell (*See Notes to Eds).

Bacteria need to stick to a host cell, before colonising and attacking it, and causing infection. They do this with the help of proteins on their outer surface called adhesins and invasins. The former attaches itself to the host cell and the latter assists the invasion. Together they define how aggressive or virulent the bacteria are at attacking the host.


Most families of adhesins belong to bacteria that cause a single disease, but the ’Dr’ family of Adhesins makes far more trouble: it is responsible for chronic diarrhoeal, intestinal and urinary tract infections, and is similar to some present in strains of Salmonella.

The researchers characterised the way in which the Dr Adhesins help bugs to cause multiple diseases because they use a very common receptor on the host cell membrane as an anchor point to attack. They target a receptor responsible for regulating one of the important human immune responses, known as Decay Acceleration Factor, or DAF.

"Cell adhesion is one of the first contacts between bacteria and host," said Dr Matthews. "Knowing the architecture of the bacteria target allows us to conceive ways to disrupt this adhesion, which may lead to potential therapeutic intervention."

Dr Matthews’ team at Imperial used nuclear magnetic resonance (NMR) spectroscopy to yield detailed insights into the structure of the two nanometre-wide Dr Adhesins.

Their work helps to resolve a long-standing debate amongst microbiologists; it leads to the reclassifying of the Dr Adhesins into a group of bacterial protein appendages known as ’fimbriae’.

These appendages are very difficult to see using the available electron microscopy techniques, and were originally classified as non-fibre or ’afimbrial’.

The new key piece of evidence emerged from some nifty protein engineering of the protein subunit, known as AfaE.

These subunits make up the fibre and cannot fold properly as proteins as they are synthesised with a piece of sequence information missing. In nature, the adjacent subunit possesses this bit of missing information, and ’lends’ it to complete the subunit and build the fibre, in a process known as donor strand complementation.

In the lab, the Imperial team artificially reintroduced the missing protein sequence so that it could complement itself and fold correctly, demonstrating that the fibres assemble in an similar fashion to fimbrial proteins.

The research was principally funded by the Wellcome Trust, and led by the Imperial team with colleagues at the Institut Pasteur, France, the Universities of Edinburgh and Oxford, the University of Texas, Case Western Reserve University, USA, and Adprotech Ltd, UK.

Tom Miller | alfa
Further information:
http://www.imperial.ac.uk

More articles from Life Sciences:

nachricht The dense vessel network regulates formation of thrombocytes in the bone marrow
25.07.2017 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg

nachricht Fungi that evolved to eat wood offer new biomass conversion tool
25.07.2017 | University of Massachusetts at Amherst

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Carbon Nanotubes Turn Electrical Current into Light-emitting Quasi-particles

Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers

Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...

Im Focus: Flexible proximity sensor creates smart surfaces

Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.

At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA mission surfs through waves in space to understand space weather

25.07.2017 | Physics and Astronomy

Strength of tectonic plates may explain shape of the Tibetan Plateau, study finds

25.07.2017 | Earth Sciences

The dense vessel network regulates formation of thrombocytes in the bone marrow

25.07.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>