Herpes simplex virus type 1 (HSV-1) uracil-DNA glycosylase: functional expression in Escherichia coli, biochemical characterization, and selective inhibition by 6-(p-n-octylanilino)uracil.

The Herpes simplex virus type 1 (HSV-1) uracil-DNA glycosylase (UDG) is encoded by the UL2 gene. The translation from the first putative start codon of UL2 predicts a polypeptide of 334 residues, while the translation from the second start codon predicts a polypeptide of 244 residues. We have cloned and expressed the two forms of UDG, by means of the prokaryotic expression vector pMAL-c2, and both of them were enzymatically active. Furthermore, the enzymatic properties of the recombinant UDGs and of the enzyme purified from HSV-1-infected cells were similar. The two UDG polypeptides have molecular weights of 27 and 37 kDa, respectively. The 37-kDa form of recombinant UDG is consistent with the reported molecular mass of 37 kDa for the enzyme purified from HSV-1-infected cells. Both recombinant UDGs were as sensitive as UDG purified from HSV-1-infected cells to 6-(p-n-octylanilino)uracil, the most potent of a series of uracil analogs that inhibit the viral enzyme.