Inside Velvet Worm Slime: Rare Protein Modification for Fast Fiber Formation

Published December 15, 2023

Two species of velvet worms and schematic representation of the phosphonoglycans that decorate the slime proteins

A protein modification rarely found in terrestrial animals was discovered in the slime of the velvet worm. This slime, which is projected for prey capture and self defence, turns into strong, sticky, water-soluble fibers. Dynamic nuclear polarization - nuclear magnetic resonance (DNP-NMR) facilities at the MagLab were used to understand the molecular structure of these fibers, work that may inspire the development and production of new classes of sustainable, advanced materials.

What did scientists discover?

MagLab users discovered an extremely unusual protein modification that involves a very rare phosphonate group and a sugar molecule that exist in large proteins created by velvet worms. These proteins float freely in fluid, but self assemble into strong fibers if they are brought close together.

Why is this important?

Velvet worms shoot out a sticky and fiber-forming slime for both catching prey and defending themselves. The more the victim struggles to escape the slime, the stronger the network of fibers becomes. Just by touching and drawing the slime, a strong fiber is formed instantly – and yet, these fibers are recyclable by adding water. This naturally occurring instance of fiber formation is highly inspiring, since understanding their assembly principles can help in the design of sustainable methods for fabricating new and advanced polymeric materials.

The protein modification is “zwitterionic” (i.e., an even number of positive and negative charges) and therefore changes the distribution of charges in the large proteins. This most likely allows the protein to self assemble into fibers because of strong electrostatic interactions and is also responsible for easy recycling of the fibers via dissolution in water. Since the properties of the fibers can be changed by altering chemical groups on the proteins (i.e., protein modifications), these experiments can provide much insight into the mechanism underlying the formation of fibers.

Who did the research?

Alexandre Poulhazan¹, Alexander Baer², Gagan Daliaho³, Frederic Mentink-Vigier⁴, Alexandre A. Arnold¹, Darren C. Browne⁵, Lars Hering², Stephanie Archer-Hartmann⁶, Lauren E. Pepi⁶, Parastoo Azadi⁶, Stephan Schmidt⁷, Georg Mayer¹, Isabelle Marcotte¹,*, Matthew J. Harrington³,*

¹Université du Québec à Montréal; ²University of Kassel; ³McGill University; ⁴National High Magnetic Field Laboratory; ⁵University of the West Indies; ⁶Complex Carbohydrate Research Center, University of Georgia; ⁷Heinrich-Heine-Universität Düsseldorf

Why did they need the MagLab?

The MagLab’s unique Dynamic Nuclear Polarization, Nuclear Magnetic Resonance (DNP-NMR) user facilities and in-house expertise enabled the decoding of the chemical structures of phosphonate and sugar molecules, uncovering another secret of nature.

Details for scientists

View or download the expert-level Science Highlight, Inside Velvet Worm Slime: Rare Protein Modification for Fast Fiber Formation
Read the full-length publication, Peculiar Phosphonate Modifications of Velvet Worm Slime Revealed by Advanced Nuclear Magnetic Resonance and Mass Spectrometry, in Journal of the American Chemical Society

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1644779, NSF DMR-2128556); F. Mentink-Vigier (NIH-GM122698); P. Azadi (NIH-R24GM137782, NSF DMR-1933525)

For more information, contact Rob Schurko.