Proteins date back to the time of sabre toothed cats

March 2, 2018, University of Western Australia
Proteins date back to the time of sabre toothed cats
Credit: University of Western Australia

Plant scientists at The University of Western Australia have discovered a completely new family of small proteins called PLPs (PawL Peptides) that form by piggybacking on other proteins.

The scientists found '-piggybacking' of PLPs began in seeds of a daisy ancestor that existed 45 million years ago during the Eocene Epoch period—around the time sabre toothed cats walked the earth.

The study included researchers from The University of Western Australia, La Trobe University in Melbourne and the University of California San Diego in the USA and has been published in the open access journal Plant Direct.

The team has previously shown that proteins like these evolved inside an unrelated protein host, but just how big this family was took them by surprise.

Using instruments capable of separating proteins before weighing them with extreme precision, the team separated and sequenced nearly 50 tiny PLPs. The structures for some were analysed using machines with strong magnetic fields used to align the atoms. Most PLPs consisted of only seven or eight amino acid blocks.

The work will help scientists understand the behaviour of proteins and could be applied in therapeutic drug treatment or even for use in nanotube devices.

Lead author Mark Fisher, Ph.D. student in UWA's School of Molecular Sciences said the research confirmed that PLPs have been around since ancient times and evolved into a huge and diverse class found among members of the daisy family.

"Super-stable peptides like these PLPs are thought to represent the next generation of drugs and we have just found dozens of them and they're unlike anything seen before," Mr Fisher said.

"For a long time, proteins this tiny were assumed to be assembled like LEGO, one amino acid block at a time. We've shown they are chopped out of much larger proteins encoded by genes.

"Their abundance and the way so many sequences are buried inside a host protein has us wondering if other valuable molecules are similarly hiding in proteins from other organisms, are just waiting to be discovered."

UWA Laboratory Head Dr. Joshua Mylne said that the work had unearthed a protein family larger than many others like it.

"For years we had been unwittingly throwing these tiny proteins in the rubbish along with all the fats and oils as we purified the proteins out of seed extracts. They are so small, they hardly behave like proteins at all.

"Now we have so many of them in our hands, it's time to work out why plants are making so many different ones in their seeds. These proteins are only found in the seeds of daisies and it's hard to know what they're doing as they vary so greatly in their properties."

Dr. Mylne led the team of Australian and US scientists that revealed this new family of proteins through the Australian Research Council-supported study "A family of small, cyclic peptides buried in preproalbumin since the Eocene epoch."

Explore further: Ancient buried treasure found in daisy seeds

More information: Mark F. Fisher et al. A family of small, cyclic peptides buried in preproalbumin since the Eocene epoch, Plant Direct (2018). DOI: 10.1002/pld3.42

Related Stories

Ancient buried treasure found in daisy seeds

March 31, 2014

( —By tracing the evolutionary origin of a drug-like protein ring found in sunflowers, Australian and US scientists have discovered a diverse, 18-million-year-old group of buried proteins in daisy seeds.

Proteins hiding in proteins take an evolutionary shortcut

March 27, 2017

How a drug-like protein ring evolved in sunflowers has been pieced together by Australian and US scientists in a study published in Molecular Biology and Evolution. Although the evolutionary process took some 45 million years, ...

Scientists reveal double life of sunflower enzyme

February 1, 2018

Scientists have explained how a protein-cutting enzyme can join the ends of proteins together, creating protein circles; a finding with immediate applications in producing therapeutic drug treatments that is published in ...

Protein doppelgangers are long-lost cousins

March 15, 2017

A 60-year-old mystery has been solved by biochemists at The University of Western Australia investigating the origin of a type of digestion-inhibiting proteins thought only to exist in two plant families that contain the ...

Cancer drug found hiding in sunflower seed protein

March 21, 2011

University of Queensland scientists have found sunflower proteins and their processing machinery are hijacked to make rogue protein rings in a discovery that could open the door to cheaper, plant-based drug manufacturing.

Recommended for you

Synthetic molecule invades double-stranded DNA

November 12, 2018

Carnegie Mellon University researchers have developed a synthetic molecule that can recognize and bind to double-stranded DNA or RNA under normal physiological conditions. The molecule could provide a new platform for developing ...

Scientists bring polymers into atomic-scale focus

November 12, 2018

From water bottles and food containers to toys and tubing, many modern materials are made of plastics. And while we produce about 110 million tons per year of synthetic polymers like polyethylene and polypropylene worldwide ...

New catalyst turns pollutant into fuel

November 12, 2018

Rather than allow power plants and industry to toss carbon dioxide into the atmosphere, incoming Rice University assistant professor Haotian Wang has a plan to convert the greenhouse gas into useful products in a green way.

Nitrogen fixation in ambient conditions

November 12, 2018

Abundant in the atmosphere, nitrogen is rarely used in the industrial production of chemicals. The most important process using nitrogen is the synthesis of ammonia used for the preparation of agricultural fertilizers.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.