Monash BDI scientists reveal structure of promising peptide fibre

Professor Mibel Aguilar and Dr Mark Del Borgo.
Professor Mibel Aguilar and Dr Mark Del Borgo.

An international collaboration led by a Monash Biomedicine Discovery Institute (BDI) researcher has shed light on the structure of a peptide that holds significant potential for drug delivery in the human body.

Peptides are amino acids that perform a broad range of essential functions in cells and tissues in the body. They link together as identical units to form polymers.

Professor Mibel Aguilar led the study into non-natural β3-peptides, the paper of which was published recently in ACS Nano.

Normally, amino acids can be linked together by harsh chemicals to make polymeric materials; β3-peptides, however, form materials without chemicals by linking together like Lego blocks, she said.

“We put our little peptide building blocks into water and they ‘zipped’ up automatically,” Professor Aguilar said.

Peptide self-assembly represented a powerful bottom-up approach to the fabrication of new nanomaterials, she said.

Unlike naturally occurring peptide polymers, β3-peptide polymers were not recognised by the enzymes that break down proteins meaning they lasted longer in the body, she said.

“When you want to put something in the body such as a gel delivering a drug you need your polymer to stay there a long time–naturally occurring peptide protein-type polymers break down quickly,” Professor Aguilar said.

Colleague Dr Mark Del Borgo discovered the peptide in 2013, but its structure and the way it assembled remained unknown until now. Knowing the structure is vital to exploiting the peptide’s potential.

The researchers collaborated with Professor Louise Serpell from the University of Sussex, UK, who used X-ray fibre diffraction to create data, and with Professor Irene Yarovsky (RMIT University) who created a high-resolution three-dimensional model using the data.

“This is the first time this atomic structure of the peptide fibre has been shown,” Professor Aguilar said.

“This is really significant because of what we want to use these materials for,” she said.

“We’ve already changed these materials to make them injectable in the body. We want to be able to decorate them and engineer them slightly differently for different disease applications.”

The researchers will develop materials aimed at helping to manage fibrosis in kidneys, and materials with cells that could be injected into the brain to potentially aid stroke recovery. They are also developing peptides that will release different drug therapies slowly into the body for people who would otherwise have to inject themselves with medications every day.

“We’ve been working on the peptides for a long time, developing drugs around them, so it’s been exciting for us to expand into the materials world,” Dr Del Borgo said.

First author on the paper was Dr Andrew Christofferson (RMIT).

Read the full text in ACS Nano titled Identifying the Coiled-Coil Triple Helix Structure of β‑Peptide Nanofibers at Atomic Resolution.

Electron micrograph and 3D structure of a helical peptide fibre.
Electron micrograph and 3D structure of a helical peptide fibre.

About the Monash Biomedicine Discovery Institute

Committed to making the discoveries that will relieve the future burden of disease, the newly established Monash Biomedicine Discovery Institute at Monash University brings together more than 120 internationally-renowned research teams. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.