Gallium Against Malaria

by David Bradley

The semiconductor gallium could help in the fight against malaria according to David Piwnica-Worms. He and his team have found a gallium complex that selectively attacks resistant strains of malaria.

Piwnica-Worms of the Mallinckrodt Institute at Washington University Medical School in St Louis Missouri has now used X-ray crystallography to elucidate the structure of their complex, which has provided clues as to how it works.

Plasmodium falciparum - the malaria parasite - extracts haemoglobin from host organisms and releases the amino acids for its own proteins. The toxic waste haem units are metabolised and stored as the inactive polymeric form, haemozoin. Conventional malaria drugs, such as chloroquine work by blocking this polymerisation process, killing the parasite. Several malaria strains have evolved resistance to this chemical attack.

The researchers found that [{1,12-bis(2-hydroxy-3-methoxybenzyl)-1,5,8,12-tetraazadodecane}gallium(III)] - or MR045 - interferes with haem polymerisation in chloroquine resistant malaria. The X-ray study showed that the Ga in MR045 cuckolds iron during haemozoin formation leading to a build-up of the toxic haem. Selectivity and bioavailibility of the drug are now being tested ready for further development.


Next item - Scanning probe microscopy

This item originally appeared in the February 1998 issue of Elemental Discoveries, David Bradley Science Writer's science webzine.

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