Zinc may starve lethal pneumonia bacteria

Researchers found that zinc can starve Streptococcus pneumoniae, a bacterium responsible for killing more than one million people annually, according to a study published on Monday in Nature Chemical Biology.

Australian scientists with the University of Queensland and the University of Adelaide determined that zinc is able to jam shut a protein transporter in the bacteria so it cannot take up manganese, an essential metal for bacterial invasion.

"It's long been known that zinc plays an important role in the body's ability to protect against bacterial infection, but this is the first time anyone has been able to show how zinc actually blocks an essential pathway causing the bacteria to starve," Christopher McDevitt, the leader of the project, said.

The study showed that the bacterial transporter, called PsaBCA, uses a spring-hammer mechanism to bind manganese and zinc. The smaller size of zinc causes the transporter to close PsaBCA too tightly and blocking it from being able to take up manganese.

"Without manganese, these bacteria can easily be cleared by the immune system," McDevitt said. "For the first time, we understand how these types of transporters function. With this new information we can start to design the next generation of antibacterial agents to target and block these essential transporters."

Streptococcus pneumoniae kills the elderly, children and other vulnerable people by causing meningitis, pneumonia and other serious infectious diseases.