FIG. 5.

(a) Size exclusion chromatography of the N-terminal domain of FIV IN (IN₅₇). FIV IN_1–57 was injected at a concentration of 0.4 mM on a Superdex 75 HR 10/30 column (Pharmacia), which had been equilibrated in buffer G (see legend to Fig. 3a). Protein markers were injected prior to each experiment (see legend to Fig. 3a). The retention time (minutes is indicated on the X axis, and the absorption at 280 nm (A₂₈₀, in arbitrary units) is depicted on the y axis. (b) Cross-complementation between FIV and HIV-2 IN mutants. Integration activities of full-length HIV-2 IN and FIV IN are depicted in lanes 1 and 4, respectively. Prior to the integration assay, an N-terminal deletion mutant of HIV-2 IN (ΔN HIV) was mixed with the N-terminal domain of HIV-2 (HIV IN₅₅) or FIV IN (FIV IN₅₇) (lanes 2 and 3, respectively). The substrate (S) mimics the U5 end of FIV; integration products (P) are indicated.