Investigating DNA Radiation Damage Using X-Ray Absorption Spectroscopy Joanna Czapla-Masztafiak, Jakub Szlachetko, Christopher J. Milne, Ewelina Lipiec, Jacinto Sá, Thomas J. Penfold, Thomas Huthwelker, Camelia Borca, Rafael Abela, Wojciech M. Kwiatek  Biophysical Journal  Volume 110, Issue 6, Pages 1304-1311 (March 2016) DOI: 10.1016/j.bpj.2016.01.031 Copyright © 2016 Biophysical Society Terms and Conditions

Figure 1 (a) Chemical structure of a fragment of DNA strand. Arrows indicate the bonds that can be broken and lead to 1) 3′ termini or 2) 5′ termini. (b) Structures of the four lesion types: 3′-phosphate, 3′-phosphoglycolate, 5′-phosphate, and CPD. Distorted PO4 groups are highlighted with orange circles. To see this figure in color, go online. Biophysical Journal 2016 110, 1304-1311DOI: (10.1016/j.bpj.2016.01.031) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 2 (a) Top: phosphorus K-edge x-ray absorption spectra of intact and UVA-irradiated aqueous DNA samples. Bottom: P K-edge XAS difference signal between the spectrum of damaged and reference DNA samples. (b) Top: phosphorus K-edge x-ray absorption spectra of intact and proton-irradiated DNA samples. Bottom: P K-edge XAS difference between the spectrum of damaged and reference DNA samples. To see this figure in color, go online. Biophysical Journal 2016 110, 1304-1311DOI: (10.1016/j.bpj.2016.01.031) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 3 (a) Comparison of the P K-edge XAS spectrum of undamaged DNA calculated in FDMNES and the experimental spectrum of nonirradiated DNA. (b) Comparison of the P K-edge XAS spectrum of ATP calculated in FDMNES and the experimental spectrum. (c) P K-edge XAS spectra for different damage sites calculated by FDMNES. To see this figure in color, go online. Biophysical Journal 2016 110, 1304-1311DOI: (10.1016/j.bpj.2016.01.031) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 4 Experimental difference of P K-edge XAS obtained for a UVA-irradiated DNA sample fitted with theoretical spectra. To see this figure in color, go online. Biophysical Journal 2016 110, 1304-1311DOI: (10.1016/j.bpj.2016.01.031) Copyright © 2016 Biophysical Society Terms and Conditions

Figure 5 Experimental difference of P K-edge XAS obtained for a proton-irradiated DNA sample fitted with theoretical spectra. To see this figure in color, go online. Biophysical Journal 2016 110, 1304-1311DOI: (10.1016/j.bpj.2016.01.031) Copyright © 2016 Biophysical Society Terms and Conditions