BBC News Online: Health

Brain diseases breakthrough

They have discovered that how ordinary proteins within the body turn into the insoluble plaques believed to be at least partly responsible for the diseases.

Researchers at Oxford University's Centre for Molecular Sciences (OCMS) carried out a series of tests which exposed myoglobin - an essential protein which stores oxygen in the body's muscle cells - to a variety of different environments, including changes in temperature and pH.

They found that the protein could adopt two distinct and highly-organised forms:

• a compact folded structure typical of most proteins in the body
• an insoluble thread-like structure typical of deposits found in the brains of many patients suffering from neurodegenerative disorders such as Alzheimer's

Evolutionary adaptation

Adoption of this structural form therefore prevents the formation of harmful deposits within the carefully regulated environment of the cells.

However, when this environment is disrupted, perhaps by age, genetic mutations or the ingestion of harmful material, the proteins can lose their folds and assume the alternative structure.

The OCMS researchers studied proteins from families with a history of brain diseases.

Their findings suggest that the folded structures of the proteins in these individuals are less stable than usual and therefore are more likely to assume the insoluble thread-like forms - making them more susceptible to disease.

The researchers believe that the discovery of these tiny molecular changes could help research into treatments for these diseases - all of which are currently incurable.

Professor Christopher Dobson, OCMS director, said: "We are a long way away from over-the-counter medicine at the moment, but our discovery does suggest new paths we can take in the search for cures.

"For example, there are compounds which might stabilise natural proteins and prevent them from converting into their alternative, disease-related structures.

"Perhaps most exciting is the prospect that, with our new knowledge of protein behaviour, we could design more stable proteins which could be administered to patients by gene therapy, but of course, this option is very much in the future."