This key discovery was made by researchers at Oxford University's Centre for Molecular Sciences (OCMS).

The researchers carried out a series of tests which exposed myoglobin -- an essential protein that 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-organized forms, a compact folded structure typical of most proteins in the body, and an insoluble thread-like structure typical of deposits found in the brains of many patients suffering from neurodegenerative disorders such as Alzheimer's.

The researchers believe that the compact fold assumed by most proteins is an evolutionary adaptation which ensures that the thread-like structure is never formed under normal circumstances by the polypeptide sequences which make up the proteins.

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.

Additional studies into proteins from families with a history of disease caused by such deposits, carried out at the OCMS, 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 family members more susceptible to disease.

The discovery of these tiny molecular changes highlights new areas in which treatments for currently incurable diseases such as CJD and Alzheimer's may be found.

Professor Christopher Dobson, Director of the OCMS, 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 stabilize 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 behavior, 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."

[Contact: Helen Carasso]

13-Mar-2001