Deadly bug-killer could replace antibiotics in therapy

Sydney, July 24 (IANS) Scientists have cracked the atomic code of a deadly bug killer, a breakthrough crowning a 40-year quest that could replace antibiotics in therapies.

Researchers from Monash (Australia) Rockefeller and Maryland (US) Universities detailed how the bacteriophage lysin, PlyC, kills bacteria causing infections from sore throats to pneumonia and streptococcal toxic shock syndrome.

Bacteriophages are viruses that infect and kill bacteria using special proteins called lysins, under investigation since 1919 for potential treatments, but abandoned with the discovery of antibiotics in the 1940s, the journal Proceedings of the National Academy of Science reports.

"PlyC, in its purified form, has been shown to be 100 times more efficient at killing certain bacteria than any other lysin to date - even faster than household bleach," said study co-author Ashley Buckle from Monash University, according to a Monash statement.

"Scientists have been trying to decipher the structure of PlyC for more than 40 years. Finally knowing what it looks like, and how it attacks bacteria, is a huge step forward," said Sheena McGowan, study co-author from Monash.

First identified in 1925, PlyC was purified in the 1960s by study author Vince Fischetti, professor from Rockefeller, but its atomic structure proved elusive until now.

Working with Fischetti (Rockefeller) and Dan Nelson (Maryland), Monash researchers James Whisstock, Ashley Buckle and Sheena McGowan, have spent the last six years deciphering the atomic structure of PlyC, to better understand its remarkable anti-bacterial properties.

McGowan said PlyC looked a little like a spaceship. "PlyC is actually made from nine separate protein 'parts' that assemble to form a very effective bacterial killing machine. It actually resembles a flying saucer carrying two warheads."

"It operates by locking onto the bacterial surface using eight separate docking sites located on one face of the saucer. The two warheads can then chew through the surface of the cell, rapidly killing the bacteria," added McGowan.

Buckle, associate professor from Monash, said the PlyC, which attacks the streptococci bacteria, was a very promising target for the future development of new drugs.