The repair of @entity6749 (Fapy) residues in DNA is performed by a Fapy-DNA glycosylase activity which is encoded for by the fpg gene in @entity526 . Besides DNA glycosylase activity, this protein, the FPG protein, is endowed with an @entity1098 -resistant activity nicking DNA at apurinic/apyrimidinic (AP) sites. To overproduce the FPG protein, the fpg gene was placed under the control of the tac promoter in the expression vector pKK223-3 yielding the pFPG230 plasmid. The production of the FPG protein in cells harboring the pFPG230 plasmid was 800-fold higher than that of the wild type strain after induction by @entity8507 . From these cells, the FPG protein was purified to homogeneity in sufficient quantity to study its physical and catalytic properties. In its active form, the FPG protein is a globular monomer of 31 kDa and has an experimentally measured isoelectric point of 8.5. When the FPG protein is heat-denatured in the presence of @entity1098 the two activities are more rapidly inactivated than when heated in the absence of @entity1098 , suggesting that the FPG protein possesses a tightly bound metal ion. Atomic absorption spectrophotometric analysis shows that there is one @entity219 /FPG protein molecule. The FPG protein is different from previously described DNA glycosylases and AP-nicking enzymes in @entity526 . The contribution of the AP-nicking activity associated with the FPG protein represents 10-20% of the total @entity1098 -resistant AP-nicking activities in @entity526 .

Homogeneous XXXX FPG protein. A DNA glycosylase which excises imidazole ring-opened purines and nicks DNA at apurinic/apyrimidinic sites.

@entity6749 :: ('MESH:C037301', 'Chemical') :: ['2,6-diamino-4-hydroxy-5-N-methyl-formamidopyrimidine'] @entity219 :: ('MESH:D015032', 'Chemical') :: ['zinc'] @entity8507 :: ('CHEBI:61448', 'Chemical') :: ['isopropyl-beta-D-thio-galactopyranoside'] @entity1098 :: ('MESH:D004492', 'Chemical') :: ['EDTA'] @entity526 :: ('562', 'Species') :: ['Escherichia coli', 'E. coli']
@entity526 :: (562,Species) :: ['Escherichia coli']
