Electron Spin Resonance of Irradiated DNA

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Science  16 Apr 1965:
Vol. 148, Issue 3668, pp. 378-380
DOI: 10.1126/science.148.3668.378


When DNA is irradiated by ultraviolet light a paramagnetic damage center is formed in the thymine bases. The structure of this free radical has been determined by electron spin resonance and consists of a hydrogen addition at the carbon No. 6 position. The rate of formation of the radical is enhanced by water vapor, and it is quenched by paramagnetic ions bound to the DNA.