Physics Commons^™

Responses Of Mn2+ Speciation In Deinococcus Radiodurans And Escherichia Coli To Γ-Radiation By Advanced Paramagnetic Resonance Methods, Ajay Sharma, Elena K. Gaidamakova, Vera Y. Matrosova, Brian Bennett, Michael J. Daly, Brian M. Hoffman

Physics Faculty Research and Publications

The remarkable ability of bacterium Deinococcus radiodurans to survive extreme doses of γ-rays (12,000 Gy), 20 times greater than Escherichia coli, is undiminished by loss of Mn-dependent superoxide dismutase (SodA). D. radiodurans radiation resistance is attributed to the accumulation of low-molecular-weight (LMW) “antioxidant” Mn²⁺–metabolite complexes that protect essential enzymes from oxidative damage. However, in vivo information about such complexes within D. radiodurans cells is lacking, and the idea that they can supplant reactive-oxygen-species (ROS)–scavenging enzymes remains controversial. In this report, measurements by advanced paramagnetic resonance techniques [electron-spin-echo (ESE)-EPR/electron nuclear double resonance/ESE envelope modulation (ESEEM)] reveal differential details …