FIG. 4.

BglII restriction analysis of donor-target products produced by different preparations of HIV-1 IN. The strand transfer products produced by three preparations of HIV-1 IN were subjected to BglII digestion. Lanes 3 and 4, IN coexpressed with protein chaperones and purified through two SP-Sepharose columns; lanes 5 to 8, IN purified identically through heparin-Sepharose that was coexpressed with (lanes 5 and 6) or without (lanes 7 and 8) chaperones. All of the HIV-1 IN preparations were tested at 25 nM in the reaction mixtures. SIV IN concentrations were 25 (lanes 1 and 2) and 50 nM (lanes 10 and 11). The wt donor DNA (P-2; diagram on right) was used. The integration products were divided into two equal samples and were not (−) or were (+) digested by BglII. Left, half-site, full-site, and donor-to-donor products; right, full-site U5-target-U5, U5-target-U3, and U3-target-U3 products produced by BglII digestion. Equivalent quantities of each set were used for comparison purposes. Only the major U5-target half-site product (circle) is apparent on this gel because of the low activity of the U3 LTR end. Lane 9, DNA molecular mass markers as described for Fig. 3.