26 February 2018

Across the Tree of Life: Radiation Resistance Gauged by High-Field EPR

Simulations of high frequency (320 GHz) high magnetic field derivative display EPR spectra of Mn2+Sod and of the Mn2+ of Dr using EasySpin. Simulations of high frequency (320 GHz) high magnetic field derivative display EPR spectra of Mn2+Sod and of the Mn2+ of Dr using EasySpin.

This high-field EPR study of the H-Mn2+ content in the bacterium Deinococcus Radiodurans provides the strongest known biological indicator of cellular ionizing radiation resistance between and within the three domains of the tree of life, with potential applications including optimization of radiotherapy.

What did scientists discover?

High field EPR Measurements performed on radiation resistant samples of Deinococcus Radiodurans (Dr) and Escherichia coli (Ec) show very little manganese superoxide dismutase (MnSOD) content.

Why is this important?

Evidence is mounting that small high-symmetry antioxidant complexes of manganous ions with metabolites (H-Mn2+) are responsible for cellular IR resistance, and that H-Mn2+ protects the proteome from IR-induced reactive oxygen species. This study disproves previous work suggesting that MnSOD is critical in the IR survival, and confirms that H-Mn2+ is the strongest known biological indicator of DNA repair efficiency and survival after gamma radiation exposure.

Who did the research?

A. Sharma1, E.K. Gaidamakova2,3, O. Grichenko2,3, V.Y. Matrosova2,3, V. Hoeke1, P. Klimenkova2,3, I. H. Conze2,4, R.P. Volpe2,3, R. Tkavc2,3, C. Gostinčar5, N. Gunde-Cimerman5, J. DiRuggiero6, I. Shuryak7, A. Ozarowski8, B.M. Hoffman1, M.J. Daly2

1Northwestern University; 2Uniformed Services University of Health Sciences; 3Henry M. Jackson Foundation for the Advancement of Military Medicine; 4University of Bielefeld; 5University of Ljubljana; 6Johns Hopkins University; 7Columbia University; 8National MagLab

Why did they need the MagLab?

THE TOOLS THEY USED

This research was conducted in the Transmission Spectrometer in the EMR Facility.

High magnetic fields provide dramatically increased spectral resolution compared to much lower field commercial spectrometers. This facilitates discrimination of paramagnetic signals from biological samples that may potentially contain multiple species. In the present case, Dr exhibits a very sharp, six-line spectrum indicative of the highly symmetric H-Mn2+ species. In contrast, MnSOD exhibits a broad multiline spectrum indicative of a strongly anisotropic Mn2+ species.

Details for scientists

Funding

This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490); B. Hoffman (NIH GM111097); M. Daly (HDTRA1620354); I Shuryak (HDTRA1-15-1-0058); J. DiRuggiero (AFOSR FA9550-14-1-0118)


For more information, contact Stephen Hill.

Details

  • Research Area: Biochemistry, Biology, Chemistry
  • Research Initiatives: Life
  • Facility / Program: EMR
  • Year: 2018
Last modified on 13 March 2018