Fig. 5.

Effect of mutations in the ⁷³WQGEQR⁷⁸ region of CBFβ on Vif–CBFβ interaction. a A ribbon diagram of HIV-1 Vif and CBFβ; Vif residues ⁴⁵ESTNPKIS⁵² are shown in orange and CBFβ residues ⁷³WQGEQR⁷⁸ are shown in purple. The dashed line indicates loop region of CBFβ that was not resolved in the structure. Vif is shown in red and CBFβ is shown in cyan (PDB: 4N9F). b After transfection of 293T cells with CBFβ-specific or control siRNA, the cells were co-transfected with WT CBFβ or double-alanine substitution mutants of CBFβ and WT Vif. Immunoblots of cell lysates (upper panel) and co-IP samples (lower panel) probed for Flag-CBFβ, endogenous CBFβ, Vif, and tubulin (loading control) are shown. c The bar graphs represent the average immunoprecipitation efficiency of the different CBFβ mutants to WT Vif relative to WT CBFβ (set to 100%). None of the mutations had a measurable effect on CBFβ levels or on Vif–CBFβ binding