[Damage mechanisms of molecule in DNA aqueous solution induced by ultraviolet radiation]

After ultraviolet radiation treated at various time, the Raman spectra of herring sperm DNA in aqueous solution were presented. The analytic results showed that first, the out-ring amino group numeration of cytosine C4 site have reducing in the form of Raman hypochromicity; but C4O ketone group of derivative uracil assumed have not emerge with Raman hyperchromiciuy, in UV-induced DNA only with water molecule join in; second, the electron cloud of the main-groove side in pyrimidine ring have a tendency of slanting toward C6 site, which was beneficial to the deamination of C-->U transition, after some cytosine formed dipyrimidine with another adjacent pyrimidine; and third, with UV radiation, the characteristic peak 616 cm-1 of uracil N3C4 has arisen. Its very important, because the quality of the N3C4 bond have a great difference between cytosine and uracil. The result have not supported the model that cytosine can direct to be come off amino group for form the ketone type uracilo depend on UV-induced, therefore we have found that the process of get involved in imino tautomer state was probable exist by Raman spectroscopic technique.