THE rotting flesh, swelling and bubbles of gas that characterise gas gangrene
are caused by a protein in bacteria that is similar to mammalian proteins.
Clostridium perfringens releases an 鈥渁lpha toxin鈥�, which bursts cells
and kills tissue. By picking apart its chemical structure, Ajit Basak, Claire
Naylor and their colleagues at Birkbeck College in London have unmasked the two
enzymes that make up the toxin (Nature Structural Biology, vol 5, p 659
and 738).
Although both enzymes help to anchor the toxin to cell walls, one鈥攚hich
binds to calcium鈥攑lays the lead role in toxicity. 鈥淚n the absence of the
calcium-binding domain, it鈥檚 much less toxic,鈥� says Basak. 鈥淲e think that the
toxin needs some calcium to activate the cell membrane and burst the cell
飞补濒濒.鈥�
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The Birkbeck team established that this enzyme resembles mammalian ones which
pass messages into cells and trigger inflammation.