Assertion: pyrimidine | /r/HasProperty | 6-4 pyrimidone photoproducts
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Source sentences:
text: UV-B radiation is one of the most important energetic solar components that may lead to the formation of three major classes of DNA lesions, such as cyclobutane pyrimidine dimers (CPDs), pyrimidine 6-4 pyrimidone photoproducts (6-4PPs), and their Dewar isomers (Figure 2) [5, 22, 23, 41–43]. CPDs correspond to the formation of a four-member ring structure involving C5 and C6 of both neighboring bases whereas 6-4PPs are formed by a noncyclic bond between C6 (of the 5′-end) and C4 (of the 3′-end) of the involved pyrimidines via spontaneous rearrangement of the oxetane (when the 3′-end is thymine) (Figure 3(a)) or azetidine (when the 3′-end is cytosine)