 This view has been challenged by data indicating that in order to increase survival, the cells must protect their proteins, which in turn repair the damage in the DNA.An important part of protection of proteins (but not DNA) against the detrimental effects of reactive oxygen species (ROS), which are the main mechanism of radiation toxicity, is played by non-enzymatic complexes of manganese ions and small organic metabolites.These complexes were shown to protect the proteins from oxidation "in vitro" and also increased radiation survival in mice.