Figure 3.

Initiation of human NER at site-directed selenophenyl or inverted C4′ backbone modifications. Excision repair reactions in HeLa cell extract were performed for 40 min at 30°C. The tested lesions and their sequence context in the duplex substrate are indicated, with the asterisks denoting the site of C4′ backbone modification. The size of oligonucleotide excision products was estimated from a 19-mer marker that is identical to the unmodified 19-mer used to construct the substrates. Lane 2 shows a control reaction with a site-specific AAF–C⁸–guanine lesion.