Thanks to simulation on a supercomputer, a team of scientists believes they have unlocked the secret of the tardigrades’ resilience.
Tardigrades, popularly known as water bears, are extremophile beings, capable of surviving in extreme situations, in the vacuum of space and negative temperatures.
Under environmental stress, such as dehydration or extreme temperatures, these tiny animals shrink into a “tun” state in which their body is almost completely inactive.
In this state, they can survive without water for decades, withstand high doses of gamma radiation and X-rays, and survive temperatures between -272 C and 150°C. For all these reasons, they are considered the toughest creatures on Earth.
In most living things, this type of environmental stress would eventually damage the cells’ DNA, but tardigrades have a protein that protects their genetic material (Dsup).
Now, a team of researchers led by Marina Minguez-Toral at the Centre for Plant Biotechnology and Genomics in Madrid, Spain, carried out a simulation of the interaction between Dsup and DNA, and the results yielded an explanation for the resilience of tardigrades.
Using a supercomputer, the team modeled a system of two Dsup molecules and DNA, composed of more than 750,000 atoms. The supercomputer took several days to complete the task.
“The equations of motion must be solved for each of these atoms 50 million times to get a simulation lasting 100 nanoseconds,” Minguez-Toral said.
The simulation of electrostatic interactions showed that the protein is “intrinsically disordered” and highly flexible, appearing to be able to adjust its structures to precisely fit the shape of the DNA.
“Our study reveals that the electrical effects underlying the positive-negative charge attractions determine the dynamics of the structural changes of Dsup in its interaction with DNA. We believe this electric shielding is paramount in protecting DNA from radiation,” Minguez-Toral concluded.
The study results were recently published in the journal Scientific Reports.