FIG. 4.

3′→5′ exonuclease activity of ASFV pE296R protein. The 5′-³²P-labeled double-stranded oligonucleotide substrate (1 pmol) was treated with the following amounts of purified pE296R protein: 35 ng (lanes 3, 8, 13, and 18), 100 ng (lanes 4, 9, 14, and 19), and 200 ng (lanes 5, 10, 15, and 20). Lanes 2, 7, 12, and 17 show control reactions with 5 units of endo IV. Lanes 1, 6, 11, and 16 show control reactions with no enzyme. The reaction products were monitored by autoradiography after resolution in a 20% polyacrylamide-7 M urea gel.