FIG. 3.

(a) Size exclusion chromatography of mutant proteins of the N-terminal domain of HIV-2 IN (amino acids 1 to 55). Proteins were injected on a Superdex 75 HR 10/30 column (Pharmacia), which had been equilibrated in buffer G (150 mM NaCl, 50 mM Tris-HCl [pH 6.7], 3 mM β-mercaptoethanol, 4 μM ZnCl₂). The following markers were used: aprotinin (6.5 kDa, 100 μg), RNase A (13.7 kDa, 125 μg), and chymotrypsinogen (25 kDa, 55 μg). Elution profiles are of the following proteins: wild-type IN₅₅ (profile A), mutant F1E;L2D;I5A (profile B), mutant F1E (profile C), and mutant H12L (profile D). Profile E is of the mutant F1E in IN_1–55 in the presence of 4 mM EDTA. All proteins were injected at a concentration of 0.4 mM. The retention time in minutes is indicated on the X axis, and the absorption at 280 nm (A₂₈₀, in arbitrary units) is shown in the Y axis. (b) Complementation between the N-terminal deletion mutant of HIV-2 IN (ΔN HIV) and several mutants of the N-terminal domain of HIV-2 IN (IN₅₅). In the first and second lanes, only IN₅₅ or ΔN is present in the reaction. The N-terminal deletion mutant was incubated with the mutants of profiles A to D of IN₅₅ (see description for panel a), prior to the integration reaction. In each two-lane panel, increasing amounts of IN₅₅ protein were added (20 and 200 pmol, respectively). The migration positions of the substrate (S) and strand transfer products (P) are indicated on the left.