XPG PROTEIN HAS A STRUCTURE-SPECIFIC ENDONUCLEASE ACTIVITY

Biochemically active human DNA repair protein, xeroderma pigmentosum G (XPG), was overexpressed in insect cells by a recombinant baculovirus . The recombinant baculovirus produced XPG with a mobility of similar to 185 kDa in a denaturing polyacrylamide gel. Indirect immunofluoresc ence studies demonstrated that the recombinant full-length XPG protein was expressed predominantly as a nuclear protein. The recombinant XPG protein was purified to apparent homogeneity using Q-sepharose, S-300 size exclusion, and Mono Q column chromatography. XPG protein showed a structure-specific DNA endonuclease activity, and a preferential aff inity to single-stranded DNA and RNA compared to double-stranded DNA.