APE1-catalyzed NIR activity towards oligonucleotide duplexes containing single Tg residue.

<p>10 nM of 3′-[³²P]-labelled 30 mer Tg-RT•A and 19 mer Tg-IW•A oligonucleotide duplexes were incubated for 30 min or 2 h at 37°C in the presence of 20 nM Fpg or 10 nM APE1 under BER+EDTA or NIR conditions, respectively. (<b>A</b>) Tg-RT•A and (<b>B</b>) Tg19•A duplexes. Lane 1, control non-treated Tg-RT•A duplex; lane 2 as 1 but treated with Fpg under BER condition for 30 min at 37°C; lane 3, as 1 but treated with APE1 for 2 h at 37°C under BER condition; lane 4, as 3 but under NIR condition; lane 5, control non-treated Tg-IW•A duplex; lane 6 as 5 but treated with Fpg under BER condition for 30 min at 37°C; lane 7, as 5 but treated with APE1 under BER condition; lane 8, as 7 but under NIR condition. For details see Materials and Methods.