AsianScientist (Nov. 18, 2013) – Australian researchers have found that zinc can ‘starve’ one of the world’s most deadly bacteria by preventing its uptake of an essential metal.
The findings, made by infectious disease researchers at the University of Adelaide and The University of Queensland in Australia, may open up opportunities for new antibacterial agents in the fight against Streptococcus pneumoniae.
Streptococcus pneumoniae is responsible for more than one million deaths a year, killing children, the elderly and other vulnerable people by causing pneumonia, meningitis and other serious infectious diseases.
In the study published in the journal Nature Chemical Biology, the researchers describe how zinc ‘jams shut’ a protein transporter in the bacteria so that it cannot take up manganese, an essential metal that Streptococcus pneumoniae needs to invade and cause disease in their human hosts.
“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,” said project leader Dr. Christopher McDevitt from University of Adelaide’s Research Center for Infectious Diseases.
According to the study, the bacterial transporter (PsaBCA) uses a ‘spring-hammer’ mechanism to bind the metals. The difference in size between the two metals, manganese and zinc, causes the transporter to bind them in different ways. The smaller size of zinc means that when it binds to the transporter, the mechanism closes too tightly around the zinc, causing an essential spring in the protein to unwind too far, jamming it shut and blocking the transporter from being able to take up manganese.
“Without manganese, these bacteria can easily be cleared by the immune system,” says McDevitt. “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.”
The article can be found at: McDevitt C et al. (2013) Imperfect coordination chemistry facilitates metal ion release in the Psa permease.
Source: University of Adelaide; Photo: AJC1/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.