Copy-cat: DNA and MfpA (right)

Matthew Vetting

Researchers have found a protein in tuberculosis bacteria that helps them resist antibiotics called fluoroquinolines. The protein's structure is remarkably similar to that of DNA.

Known as MfpA, the protein twists to mimic a DNA double helix. The two are also of similar widths.

John Blanchard of Albert Einstein College of Medicine in the United States and colleagues published these findings today (3 June) in Science.

Antibiotics kill tuberculosis by binding to the bacteria's DNA, which stop it from replicating. The scientists showed that when MfpA is produced, the antibiotic binds to it instead of to the DNA. Although replication of the tuberculosis DNA is still reduced by the antibiotic, it is not halted entirely.

The researchers warn that the process they have shown in the laboratory is not the one responsible for fluoroquinoline-resistance in tuberculosis strains isolated from people. But they add that the results could be used to create a new class of antibiotics.

Link to full article in Science news story

Link to full research paper in Science

Reference: Science 308, 1480 (2005)