The key to impeding drug resistance in bacteria

Researchers have solved the structure of a DNA-protein complex that is crucial in the spread of antibiotic resistance among bacteria, providing insights into how cells successfully divide into two new cells with intact DNA.

Published in the 20 December issue of Nature, the report focuses on how DNA separates and maintains its integrity when a cell divides. Using X-ray crystallography, structural biologists at The University of Texas M D Anderson Cancer Center and colleagues at the University of Sydney produced clear 3D images of the structure that results when two proteins connect with a DNA site to 'segregate' DNA during cell division.

"We solve structures to answer questions about how molecules carry out their biological functions. Without knowing the structure, you can't understand molecular mechanisms at a detailed level," said lead author Maria Schumacher, associate professor in M D Anderson's Department of Biochemistry and Molecular Biology.

In the report, Schumacher and colleagues answer a basic science question and identify a possible target against antibiotic-resistant S. aureas (MRSA).

"The plasmid segregation system we are working on, called pSK41, is found in S. aureus and confers resistance to multiple antibiotics, including the drug of last resort, vancomycin," Schumacher said.

"Because the segregation systems are essential for the retention of these multidrug-resistant plasmids, they represent wonderful drug targets."