October 17, 2008

Study Shows New Class Of Antibiotics

Researchers said on Thursday that three naturally occurring antibacterial compounds hold promise for a new class of antibiotics, offering hope for fresh weapons against infection at a time when older drugs are losing their punch.

The new agents may even provide a quicker cure for tuberculosis.

"The three antibiotics are attractive candidates for development as broad spectrum antibacterial agents," said Richard Ebright of Rutgers University in New Brunswick, New Jersey.

Ebright and colleagues showed how myxopyronin, corallopyronin and ripostatin block the action of bacterial RNA polymerase.  They found blocking this enzyme kills the bacteria.

All three of the compounds are naturally produced by bacteria for use in a kind of chemical warfare against other bacteria. The agents work by taking advantage of a design flaw in bacterial RNA polymerase.

"RNA polymerase has a shape reminiscent of a crab claw, with two prominent pincer-like projections," Ebright said in a statement.

"Just as with a real crab claw, one pincer stays fixed and one pincer moves -- opening and closing to keep DNA in place."

All three antibiotics work by jamming the pincer hinge, keeping the bacteria from letting DNA into the enzyme.  The bacteria cannot make proteins without the needed genetic code.

The understanding of this allows the researchers to find ways to tinker with chemical structure of the antibiotic targets to make them more potent.

The compounds appear to work against a broad range of bacteria.

"As a result, these antibiotics can function simultaneously with rifamycins and can be co-administered with rifamycins for more rapid clearance of infection," Ebright said.


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