Some proteins can survive without water - and now we know how

Proteins keep our cells alive and functioning, but both depend deeply on water. Take that water away, and everything unravels – cells shrivel, proteins misfold, and life grinds to a halt.

Dehydration is usually fatal for living things – but not for all of them. Certain plants, fungi, and microscopic animals called tardigrades can dry out completely, stay dormant, and then spring back to life once water returns.

Scientists have known about this phenomenon for a while. What they haven’t known is how it works.

What makes the difference between life and death when water disappears? A team of researchers just got us closer to the answer.

Proteins that resist dehydration

Proteins do most of the work inside cells. They’re involved in everything from building new molecules to processing energy. But they’re also fragile.

In most living things, proteins don’t survive dehydration. They lose their shape and stop functioning – even after water is added back in.

To find out how some proteins can endure, researchers turned to yeast. It is simple, well-studied, and easy to manipulate in the lab.

Largest test of its kind

The researchers looked at thousands of different proteins, studying how well they handled dehydration and rehydration. It’s the first time anyone has run this kind of large-scale test.

The team used mass spectrometry to track protein survival rates and AI tools to analyze protein structure and chemistry. The results showed a big difference in survival depending on the type of protein.

Shahar Sukenik, the study’s lead author, is an assistant professor in the Department of Chemistry at Syracuse University.

“Most proteins will lose over three-quarters of their copies following a dehydration-rehydration cycle,” said Sukenik. “But some proteins do much better, with a large majority of their copies surviving the process.”

Key features in surviving proteins

The proteins that made it through dehydration shared some key features. They were usually small, tightly folded, and had very specific chemical properties.

One standout trait? Their surfaces were packed with negative charges. Those negative charges seem to help the proteins stay intact when water dissipates, and even when it returns.

The team didn’t stop there. They tested whether they could build a more tolerant protein using what they learned. They picked a protein called Green Fluorescent Protein (GFP), which normally doesn’t handle drying well.

By changing parts of GFP’s structure, based on the rules they discovered, they managed to create a version that stayed almost completely active after dehydration and rehydration. Nearly 100% of it survived the process.

Not all proteins are equal

The study also uncovered something interesting about the purpose of these proteins.

Those that survived dehydration weren’t just chemically special; they were also functionally important. They tended to be “producer” proteins, those that make small molecules used to build everything else in the cell.

“If the cell runs out of these small building blocks for whatever reason, that’s it. The cell is stuck. It’s like a car running out of gas,” Sukenik said.

On the other hand, the ones that fell apart were often involved in energy-intensive tasks like building ribosomes, the machines that make new proteins. During water loss, they become too expensive to keep around.

Yeast cells seem to have figured this out. During dehydration, they protected the proteins that produce critical building blocks. At the same time, they released those that would burn through those supplies too quickly.

“We think these ‘producer’ proteins have evolved to develop the specific chemistry that allows them to rehydrate, so when water hits the dehydrated cell, they kick into action and enrich the environment with the building blocks they produce,” said Sukenik.

Changing how we think about biology

Until now, scientists thought desiccation tolerance was something rare; something only a few “extreme” organisms could do. This study suggests otherwise.

The ability to survive dehydration might not be about what species you are. It could come down to the chemical “grammar” written into your proteins.

That opens the door to designing new proteins with built-in resistance to drying out, and that could mean big things for biotechnology.

Having the ability to engineer proteins to stay stable without water offers the opportunity to store them longer, ship them more easily, and skip the necessity for refrigeration.

“During the COVID-19 pandemic, there were problems in cold chain delivery, which hindered access to vaccines,” said Sukenik.

“But when your product is dehydrated, you won’t have to keep it cold. The shelf life of medicines, food, or other protein-based products could be extended by months or even years.”

The limits of life’s capabilities

The study doesn’t just explain how some organisms survive water loss. It also gives us the tools to build proteins that can do the same thing on demand.

Ultimately, this could change how we store food and deliver medicine.

The research also expands what we know about life’s capabilities. And it all starts with an understanding of what makes a protein survive when everything else dries up.

The full study was published in the journal Cell Systems.

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