Due to its unique features – duck-billed, egg-laying, beaver-tailed and venomous- the platypus has always appealed to scientists, making it an important subject in the study of evolutionary biology. In 2010, it was found that platypus milk contained unique antibacterial properties that could be used to fight superbugs.
Now a team of researchers at CSIRO working with Deakin University have solved a puzzle that helps explain why platypus milk is so potent – bringing it one step closer to being used to save lives.
The discovery was made by replicating a special protein contained in platypus milk in a laboratory setting.
“Platypus are such weird animals that it would make sense for them to have weird biochemistry,” says CSIRO scientist and lead researcher Dr Janet Newman.
“The platypus belongs to the monotreme family, a small group of mammals that lay eggs and produce milk to feed their young. By taking a closer look at their milk, we’ve characterised a new protein that has unique antibacterial properties with the potential to save lives.”
As platypus don’t have teats, they express milk onto their belly for the young to suckle. This exposure of the mother’s highly nutritious milk to the environment leaves babies susceptible to the perils of bacteria. Researchers believe this is why the platypus milk contains a protein with rather unusual and protective antibacterial characteristics.
“We were interested to examine the protein’s structure and characteristics to find out exactly what part of the protein was doing what,” says Deakin University’s Dr Julie Sharp.
Using a synchrotron and CSIRO’s state of the art Collaborative Crystallisation Centre (C3) the team successfully created the protein, then deciphered its structure to get a better look at it.
What they found was a unique, never-before-seen three dimensional fold shaped like a ringlet and dubbed the ‘Shirley Temple’, referencing the former child star’s distinctive curly hair.
Dr Newman said finding the new protein fold was a significant breakthrough. “Although we’ve identified this highly unusual protein as only existing in monotremes, this discovery increases our knowledge of protein structures in general, and will go on to inform other drug discovery work done at the Centre.”In 2014, the World Health Organisation released a report highlighting the scale of the global threat posed by antibiotic resistance, pleading for urgent action to avoid a “post-antibiotic era”, where common infections and minor injuries, which have been treatable for decades, can once again kill. Antibiotics building up a resistance and then passing that resistance on to their next generation leads to ineffective treatments and more persistent infections caused by these resistant superbugs.