Researchers in Scotland and Thailand have made a breakthrough in the battle against malaria, a mosquito-borne, parasitic illness that kills between one and three million people each year around the world. They have isolated a protein that has made the disease resistant to current treatments.

The protein produced by the malaria parasite is called DHFR, which has made traditional, anti-malarial drugs increasingly ineffective during the past 30 years.

Researchers have known about the DHFR molecule for some time. But they have used one drug compound after another against the protein in an effort to make the parasite sensitive to anti-malarial drugs.

Now, researchers at Thailand's Biotec Institute and Edinburgh University in Scotland have isolated the mutated form of DHFR. Professor Malcolm Walkinshaw of Edinburgh University says they have taken very clear, detailed pictures of both normal DHFR and mutated DHFR.

"If you are fixing a machine or a car engine or something in the dark with no plans, this is like having the light turned on and being able to see the plans and see what you need to do," Professor Walkinshaw said.

Professor Walkinshaw said researchers now have a complete, three-dimensional map of DHFR. The finding will help them develop or improve drugs that target specific places on the surface of the DHFR molecule to keep it from producing the stealth molecule.

"It gives us a very clear path to follow of what requirements we need on the new drug. Maybe it just needs small changes, small structural changes, in the existing types of molecules that will make them bind better and fit around these changes in the shape that the parasite has evolved," he said.

The team's findings were published in the journal Nature Structural Biology.

Professor Walkinshaw is certain the malaria parasite will eventually become resistant to new drugs that are likely to follow his work. But for the first time, scientists will have the chance to stay ahead of the parasite.