Long-range oxidative damage to cytosines in duplex DNA

Shao et al. 10.1073/pnas.0408128101.

Supporting Information

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Supporting Figure 5
Supporting Figure 6

Supporting Figure 5

Fig. 5. Photooxidation of N₄-cyclopropylcytidine (r^CPC) by Rh(phi)₂(bpy′)³⁺ (Rh). Thirty-microliter aliquots of 250 m M r^CPC, 25 m M Rh in 50 mM NaCl, and 10 mM sodium phosphate (pH 7.0) were irradiated at 365 nm for 40 min. Shown are the HPLC traces before (blue) and after (red) irradiation; r^CPC decomposed to produce two major products, rC and r^HPC. The products were confirmed by MS: M.W. (rC) = 243; M.W. (r^HPC) = 315. Similar results were obtained with anthraquinone (AQ).

Supporting Figure 6

Fig. 6. DNA-mediated photooxidation of N₄-cyclopropylcytosine (^CPC) by Rh is an intraduplex reaction. Duplexes containing Rh without ^CPC (Rh-I-1/C-1) and containing ^CPC without Rh (I-1/Cp-1) were mixed after annealing separately (30-m l aliquots of 5 m M each duplex in 50 mM NaCl and 10 mM sodium phosphate, pH 7.0). Shown are the HPLC traces of the enzymatically digested duplexes before (a) and after (b) 40 min of irradiation at 365 nm. No decomposition of ^CPC is detected when Rh and ^CPC are not within the same duplex. The analogous interduplex control was also conducted by using AQ-tethered assemblies where, again, no interduplex reaction was detected.