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Crushing resistance

THE commonest form of antibiotic resistance can be defeated by a small change
to the drug molecule, according to Shahriar Mobashery, a chemist at Wayne State
University in Detroit.

Bacteria commonly become resistant to antibiotics by generating enzymes that
attach a phosphate group to the antibiotic molecule in place of a hydroxyl
group. The phosphate group prevents the antibiotic binding to the bacteria,
disarming the drug.

In a paper to be published in the Journal of the American Chemical
Society, Mobashery reports that attaching a second hydroxyl group to the
antibiotic kanamycin A foils this strategy by destabilising the phosphate bond.
“The enzyme puts the phosphate on, but it can’t stay put and so it falls offâ€
says Mobashery. In general, the extra hydroxyl should not alter the
effectiveness of antibiotics.