A citric-acid based Achilles heel used by a pathogen that attacks the African Violet pot plant could produce a treatment for anthrax.
Researchers at the University of Warwick made this discovery after examining the assembly of a chemical structure in Pectobacterium chrysanthemi (Dickya dadantii), a bacterial pathogen that afflicts plants, particularly the African Violet.
Like many bacteria, Pectobacterium chrysanthemi competes with its host for iron, without which the bacterium cannot grow.
The University of Warwick researchers Dr Nadia Kadi, Dr Daniel Oves-Costales, Dr Lijiang Song and Professor Gregory Challis worked with colleagues at St Andrews University to examine how a siderophore, a tool the bacterium uses to harvest iron, is assembled.
They discovered how achromobactin, an enzyme catalyst in the assembly of this particular siderophore, binds citric acid, a vital iron-binding component of the structure.
Their findings show that this chemical pathway could be blocked or inhibited to prevent the bacterium from harvesting iron, essentially starving it.
The research team found this had major implications for treating several virulent infections, including anthrax.
A second piece of research conducted by three of the University of Warwick researchers found that the deadly pathogen that causes anthrax in humans uses an enzyme to incorporate citric acid into another siderophore that is similar to the one used by the African Violet pathogen.
The researchers showed that both enzymes recognise citric acid in the same way.
This means a common strategy could be used to block the anthrax and African Violet pathogen siderophore synthesis pathways.
Professor Greg Challis, from the University of Warwick, said: 'Inhibiting this citric-acid based process could be even more effective in combating an anthrax infection than it would be in combating the African Violet pathogen.
'This is because the African Violet pathogen has a second siderophore that can harvest iron from the host and could attempt to struggle on with just this, whereas the anthrax pathogen appears not to have such a back-up mechanism.' This new discovery could lead to the design of drugs that may eliminate the anthrax pathogen's ability to harvest iron and stop an infection dead in its tracks.
A respiratory anthrax infection is nearly always fatal but this discovery opens new possibilities for combating such infections.
The researchers are now looking at similar enzymes involved in the assembly of citric-acid derived siderophores in E.coli and MRSA, which may offer further targets for drug development.
Funding for the research reported in both papers was provided by the Biotechnology and Biological Sciences Research Council (BBSRC).
