Tough tardigrades: Microscopic water bears can withstand harmful radiation, thanks to a certain protein

A protein found only in tardigrades may protect cells from DNA damage caused by radiation exposure, according to a recent study published in eLife. Researchers from the University of California, San Diego examined the protective properties of a damage-suppressing protein called Dsup and found that it has a cloud-like structure that shields cell components from free radicals.

According to coauthor James Kadonaga, this finding can help scientists develop other types of proteins that are even more effective at protecting cells from radiation.

“You can have more-durable cells, more-longer-lived cells. That might be a case for putting some form of Dsup in that cell,” said Kadonaga.

Dsup shields DNA from free radicals

Tardigrades are notoriously tough; they have the remarkable ability to weather extreme conditions, such as high levels of cosmic radiation and freezing and boiling temperatures. The researchers wanted to explore the chemical properties that lend tardigrades their hardiness. They focused on Dsup, which is found only in the tardigrade species Ramazzottius varieornatus.

Studying the protein could reveal this species’ unique capabilities as other proteins that make tardigrades so tough are also found in other organisms. Previous research also found that when Dsup was introduced to human cells, it could safeguard them against DNA damage.

In the latest study, the team looked into the mechanisms behind the protein’s protective effects. They found that Dsup binds to chromatin, a cellular structure that holds long strands of DNA in a dense package. The protein’s cloud-like structure surrounded the chromatin envelope and blocked hydroxyl radicals – highly reactive particles of oxygen and hydrogen that are formed when X-ray comes into contact with water. They could damage the DNA packaged within chromatin.

“Now that we know how it worked, that’s a stepping stone to potentially using it for practical applications,” Kadonaga said.

Disorderly nature helps Dsup adjust itself to DNA

Another study, published in the journal Scientific Reports, further shed light on the anti-radiation properties of Dsup. This time, researchers from the Polytechnic University of Madrid posited that the protein may be adjusting itself to conform to the structure of DNA.

The researchers developed a model simulating the arrangement of Dsup’s amino acid components using genetic sequences from the same tardigrade species. They also made a similar model for another protein that’s a near match for Dsup, which is found in the tardigrade species, Hypsibius exemplaris.

“Our results suggest that the protein is intrinsically disordered, which enables Dsup to adjust its structure to fit DNA shape,” wrote the researchers. (Related: Eight-legged tardigrades are the ultimate doomsday survivors and can live 30 years without food or water.)

Besides this disordered nature, they posited that strong electrostatic attractions drive the formation of a molecular shield around the DNA. However, they added that the precise mechanisms behind Dsup’s protective action would have to be further explored. It’s also worth considering how radiation affects Dsup on a physical level.

Knowing the answer to these mysteries would help elucidate how Dsup can be practically used to boost radiation protection. In turn, having such immunity can help minimize the harmful effects of radiation, such as skin burns, cancer and cardiovascular disease.

Read more research on Dsup’s anti-radiation properties at Radiation.news.

Sources include:

LiveScience.com

ScienceAlert.com

EPA.gov