Pneumonia-causing pathogen from copper.

• Position: Pathogens - Brief article

Bacterial pathogens like Streptococcus pneumoniae--responsible for infections that include pneumonia, meningitis, and sepsis--have evolved various strategies to limit copper levels in their cells to prevent toxicity.

"Copper is highly reactive metal and is carefully handled by all cells that require it," points out David Giedroc, professor of chemistry at Indiana University, Bloomington. "There is emerging evidence to suggest that human cells use copper toxicity as a weapon to kill microbial pathogens. The novel copper trafficking system that we describe in our study represents a new functional twist on an evolutionary ancient family of proteins that opens up a potential new antibacterial strategy."

Giedroc and his coworkers describe the structure and function of the protein Cup A as a chaperone that buffers copper to very low concentration--in turn protecting S. pneumoniae from damage.

"We're proposing that the primary role of...