Fig. 2.

Repair an AP site (■), a THF lesion (•) and a dL lesion (▴) by purified LP-BER proteins. (A) Phosphorimaging scan showing the products of the repair assay. LP-BER was reconstituted with purified proteins, adding in one protein at a time to see all steps of repair. For dL conversion (–) and (+) denote treatment with NaOH to determine if the dL conversion was successful (see Section 2). 5′ and 3′ refer to ³²P-labeling of the 5′ or 3′ terminus. (B) Total repair as measured by restitution of the intact strand. Reaction contains APE1, polymerase β, FEN1 and ligase1. (C) APE1 activity as measured by cleavage of the intact strand to create a SSB. Reaction contains APE1 only. (D) Polymerase β activity as measured by incorporation of bases. Reaction contains APE1 and polymerase β. (E) FEN1 activity as measured by removal of the DNA flap created by strand displacement. Reaction contains APE1, polymerase β and FEN1. Error bars show standard error of the mean from three experiments.