Researchers are unlocking the molecular secrets behind a unique bacterium that has a superpower for survival in some of the most extreme conditions, including exposure to massive amounts of radiation that would harm most organisms.
Deinococcus radiodurans has long fascinated scientists, primarily because of its resilience to radiation effects. Now, new research from Northwestern University is helping to reveal how this hearty bacterium can withstand otherwise potentially deadly conditions.
Barbarians of the Bacterial Realm
Given its resilience, D. radiodurans has garnered the nickname “Conan the Bacterium,” a nod to Robert E. Howard’s famous dark warrior hero that launched the sword and sorcery genre of fiction in pulp magazine articles published in the 1930s.
Like Howard’s famous barbarian character, D. radiodurans has a unique ability to overcome the dangers it encounters, although precisely what makes the bacterium so strong has remained mysterious until now.
According to findings by a Northwestern University team in collaboration with the Uniformed Services University (USU), the bacterium boasts a unique antioxidant complex that combines manganese, phosphate, and specific peptides.
Revealing the key to the bacterium’s resilience could mean more than unlocking the secrets of an unusual, simple organism, however. The researchers involved with the research believe their findings could point the way toward new technologies and treatments, which may even include the development of radiation-based vaccines.
Armed with Antioxidants
D. radiodurans has been shown to be capable of withstanding exposure to radiation doses thousands of times more potent than what would kill humans. According to the Northwestern team, this remarkable natural shielding results from a relatively simple process: metabolites that combine with manganese, which helps produce a surprisingly potent antioxidant complex.
The discovery highlights a breakthrough in our knowledge of microbial resilience at the molecular level and inspired the team to develop a new synthetic antioxidant modeled after the barbaric bacterium’s remarkable protective system.
Dubbed MDP, the team’s synthetic antioxidant combines manganese ions with phosphate and a small peptide. This produces a ternary complex—essentially a complex of proteins composed of three bound molecules—that is far more effective at blocking damage from radiation when combined than when its individual components face it alone.
“It is this ternary complex that makes MDP an extraordinary shield against radiation,” explained Northwestern’s Brian Hoffman, who collaborated with USU’s Michael Daly. “We’ve long understood manganese and phosphate form a strong antioxidant, but adding the peptide enhances its protective power exponentially.”
Hoffman, a molecular biosciences professor at Northwestern, and Daly, a professor of pathology at USU and a planetary protection expert, have studied the bacterium for years. Such a powerful antioxidant could have a range of beneficial applications, including protecting astronauts against harmful cosmic radiation they’ll encounter during deep-space missions.
Other possibilities include new approaches to emergency radiation treatments and advancing vaccine production with radiation-inactivation capabilities. Fundamentally, the team’s findings could help redefine strategies involving radioprotection in healthcare, defense systems, and space exploration.
Surviving in a Frozen Alien Landscape
Past studies have also revealed that D. radiodurans, while able to survive as much as 25,000 grays of radiation under normal conditions, can withstand almost five times as much when the bacterium is dried or frozen. That’s roughly the equivalent of 28,000 times the amount of radiation that would be a lethal dose for humans.
One intriguing implication of such findings is that similar microbes, if they existed in a dormant state while buried on Mars, could potentially also withstand exposure to radiation in such environments.
“This new molecular insight opens the door to transformative applications,” Daly noted. “From creating advanced radiation shielding to developing next-generation vaccines, the possibilities are truly promising.”
Right now, Hoffman, Daly, and their colleagues aim to progress with their understanding of MDP’s ternary complex and eventually design similar, even stronger manganese-based synthetic antioxidants that, like the hearty D. radiodurans, might enhance the survival of various organisms in the otherwise inhospitable conditions of space.
The team’s study, “The ternary complex of Mn2+, synthetic decapeptide DP1 (DEHGTAVMLK) and orthophosphate is a superb antioxidant,” was published in Proceedings of the National Academy of Sciences on December 12, 2024.
Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. He can be reached by email at micah@thedebrief.org. Follow his work at micahhanks.com and on X: @MicahHanks.