Deinococcus radiodurans, often referred to as "Conan the Bacterium," is renowned for its remarkable ability to endure extreme radiation levels. This bacterium can withstand doses of radiation that are 28,000 times greater than what would be lethal to humans. The key to this resilience lies in a combination of simple metabolites and manganese, forming a potent antioxidant.
Researchers from Northwestern University and the Uniformed Services University (USU) have made significant progress in understanding how this antioxidant functions. They have characterized a synthetic designer antioxidant named MDP, inspired by Deinococcus radiodurans' resistance. MDP consists of manganese ions, phosphate, and a small peptide that together form a ternary complex offering superior protection against radiation compared to manganese combined with either component alone.
This discovery has potential applications in developing new synthetic antioxidants tailored for human use. Such advancements could protect astronauts from cosmic radiation during space missions, prepare for radiation emergencies, and aid in producing vaccines through radiation-inactivation methods.
The study will be published in the Proceedings of the National Academy of Sciences during the week of December 9th. Brian Hoffman from Northwestern University stated, “It is this ternary complex that is MDP’s superb shield against the effects of radiation.” He emphasized the breakthrough achieved by adding a third component to enhance potency.
Hoffman holds positions as Charles E. and Emma H. Morrison Professor of Chemistry and professor of molecular biosciences at Northwestern's Weinberg College of Arts and Sciences. His collaborator Michael Daly is a professor at USU and part of the National Academies’ Committee on Planetary Protection.
The research builds on previous studies by Hoffman and Daly exploring Deinococcus radiodurans' ability to survive Martian conditions. Their work revealed that higher concentrations of manganese antioxidants correlate with increased resistance to intense radiation.
Earlier studies showed Deinococcus radiodurans surviving 25,000 grays of x- and gamma-rays; however, Hoffman and Daly found it could endure up to 140,000 grays when dried and frozen—a dose far exceeding human tolerance.
Further investigation into the microbe's resistance led Hoffman and Daly's team to explore DP1—a designer decapeptide forming MDP when combined with phosphate and manganese. This agent effectively protects cells from radiation damage.
Daly noted that understanding MDP could lead to more powerful manganese-based antioxidants for healthcare, industry, defense, and space exploration applications.
The study titled “The ternary complex of Mn2+, synthetic decapeptide DP1 (DEHGTAVMLK) and orthophosphate is a superb antioxidant” received support from several institutions including the National Institutes of Health (grant GM111097), National Science Foundation (grant CHE-2333907), and Defense Threat Reduction Agency (grant HDTRA1620354).