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Wednesday, 23 January, 2002, 19:55 GMT
Anthrax toxin fully exposed
Bacteria, AP
Three proteins make the anthrax bacteria deadly
Scientists have obtained information that should help them find new ways to block the effects of an anthrax infection.

The researchers have worked out the shape of another of the dangerous molecules the bacterium uses to attack the human body.

The team behind the discovery says its work, and other studies recently completed on the bug more formally known as Bacillus anthracis, should open the way for the development of better drug treatments.

"We've expanded vastly the depths of our understanding," Andrew Bohm of the Boston Medical Research Institute, US, said. "A few years down the road, one or more of these developments will lead to new therapeutics."

Body's messengers

The anthrax toxin comprises three proteins. When they work together, they can kill humans, especially after spores of the bacteria have been inhaled.

Bacteria, AP
Investigations into the recent US cases are ongoing
One of the proteins shields the other two from the body's immune system; the second destroys immune-system cells.

The third molecule, called oedema factor (EF), hijacks the signaling system in the body. This disrupts the energy balance of cells and leads to them accumulating fluid.

Patients haemorrhage and die from a form of septic shock.

Scientists published the structures of the first two proteins last year. This week, again in the journal Nature, researchers reveal the precise shape of the EF molecule and the way it binds with an important messenger molecule in the bloodstream.

Tested on mice

Knowing the exact arrangement of the atoms in the three toxin molecules will enable pharmaceutical companies to design drug compounds that block the activity of the proteins.

Andrew Bohm and colleagues say they can see a deep "pocket" on the side of the EF protein which is crucial for its activity and could prove a fruitful target.

At present, only one anthrax vaccine exists for humans but others are in development. One promising new vaccine which has been tested on mice was announced by French researchers earlier this week.

Current antibiotics - used to treat patients once they have become infected - are highly successful, provided they are given early enough.

See also:

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23 Oct 01 | Health
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05 Nov 01 | Health
New anthrax vaccine created
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