Effect of the ionic strength on the stability of the ternary complex chromatin LEDGF/p75-HIV-1 integrase. (a) The chromatin binding strength of the complex HIV-1 integrase-LEDGF/p75 was determined by the salt extraction method in LEDGF/p75-deficient HEK293T cells stably coexpressing Myc-tagged integrase and LEDGF/p75 WT, ΔPWWP or ΔPWWP/AT. Myc-integrase was determined by immunoblotting using an anti-Myc Mab. (b) Effect of salt concentration on the non-chromatin bound HIV-1 integrase-LEDGF/p75 complex. The integrase-LEDGF/p75 complex bound to anti-LEDGF Mab coupled-magnetic beads was incubated in CSK I buffer supplemented with different NaCl concentrations and LEDGF/p75 and integrase were determined by immunoblotting with anti-LEDGF and anti-Myc Mabs, respectively, in the immunocomplex-bound to the magnetic beads or in the eluated fractions.