A building block for bacterial virulence factors

Researchers from the University of Adelaide have identified a building block common to many types of bacterial virulence factors - ie, the bacterial proteins which act as weapons to cause disease. The research has been published in the journal Molecular Microbiology.

As explained by the study’s first author, Matthew Doyle, “Bacteria can only cause disease when virulence factors are appropriately produced by the bacteria and transported (or secreted) onto the cell surface where they become harmful.” The newly discovered building block, called the Passenger-associated Transport Repeat (PATR), is integral in the transport of the virulence factors to the surface of the bacterial cell.

PATR has been found in virulence factors of many major harmful bacteria, including Salmonella, Shigella and Meningococcus; bacteria that cause infections in cystic fibrosis and burns patients; and many major Gram-negative bacteria, including those that have developed resistance to a broad range of antibiotics. According to Doyle, PATR is “shared by thousands of common virulence factors produced by many major pathogenic bacteria” and is “crucial for those virulence factors to mature appropriately”.

“We initially could not believe that this building block has been overlooked,” added corresponding author Associate Professor Renato Morona, who has spent over a decade looking at how bacteria cause disease. “We’ve discovered something that’s been hidden in plain sight.”

Doyle noted that the discovery of PATR may lead to the possibility of its suppression, via the “development of a completely new class of broad-spectrum bacterial virulence inhibitors”. The breakthrough will also be useful for the development of a variety of biotechnology products and processes which rely on coupling biological molecules to cell surfaces.

“It may shift the way research in this field is conducted,” Associate Professor Morona said.

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