EFFECT OF MID-UV RADIATION ON DNA-Cu2+ COMPLEX: ABSORPTION AND CIRCULAR DICHROISM STUDY |
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| Authors: | Mirella Matzeu Giuseppe Onori |
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| Institution: | Laboratorio di Fisica, Istituto Superiore di Sanitàand Istituto Nazionale di Fisica Nuclease, Sezione Sanite, Rome, Italy;Dipartimento di Fisica, Universitàdi Perugia. Perugia. Italy |
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| Abstract: | Abstract— When DNA is complexed with Cu2+ ions it becomes sensitized to mid-UV light. Irradiation of the complex at 310 ± 10 nm produces marked changes in absorption and circular dichroism spectra in addition to those in melting profiles of irradiated samples. These variations show conformational changes in DNA structure due to a photoreduction of some copper sites in the DNA-Cu2+ complex. In addition to this effect an irreversible damage in DNA structure could be invoked to explain the observed behaviour. These facts can be related to the presence in DNA-Cu2+ complex of a small absorption band extending up to mid-UV range while the absorption of DNA is negligible in this spectral range. |
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