Figure 1.

Coelution of zinc with HIV-1 integrase in gel filtration. Integrase was dialyzed against buffer A containing zinc chloride as described and applied to a Superdex 75 column equilibrated with buffer A not containing zinc. The protein concentration in each of the collected fractions was determined by measuring the optical density at 280 nm, and the zinc concentration in the same fractions was determined by atomic absorption spectroscopy. (A) Full-length integrase (IN^1–288/F185K/C280S). (B) Integrase with a C-terminal deletion (IN^1–212/F185K). (C) Integrase with an N-terminal deletion (IN^50–288/F185K/C280S). (D) The central domain of integrase (IN^50–212/F185K). (E) Integrase with the His residues of the HHCC motif changed to Asn (IN^1–288/H12N/H16N/F185K/C280S).