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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