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Core-binding factor β increases the affinity between human Cullin 5 and HIV-1 Vif within an E3 ligase complex.

HIV-1 Vif masquerades as a receptor for a cellular E3 ligase harboring Elongin B, Elongin C, and Cullin 5 (EloB/C/Cul5) proteins that facilitate degradation of the antiretroviral factor APOBEC3G (A3G). This Vif-mediated activity requires human core-binding factor β (CBFβ) in contrast to cellular substrate receptors. We observed calorimetrically that Cul5 binds tighter to full-length Vif((1-192))/EloB/C/CBFβ (K(d) = 5 ± 2 nM) than to Vif((95-192))/EloB/C (K(d) = 327 ± 40 nM), which cannot bind CBFβ. A comparison of heat capacity changes supports a model in which CBFβ prestabilizes Vif((1-192)) relative to Vif((95-192)), consistent with a stronger interaction of Cul5 with Vif's C-terminal Zn(2+)-binding motif. An additional interface between Cul5 and an N-terminal region of Vif appears to be plausible, which has therapeutic design implications.

Pubmed ID: 23098073


  • Salter JD
  • Lippa GM
  • Belashov IA
  • Wedekind JE



Publication Data

November 6, 2012

Associated Grants

  • Agency: NIAID NIH HHS, Id: R33 AI076085
  • Agency: NIAID NIH HHS, Id: R33 AI076085

Mesh Terms

  • Core Binding Factor beta Subunit
  • Cullin Proteins
  • Humans
  • Thermodynamics
  • Ubiquitin-Protein Ligases
  • vif Gene Products, Human Immunodeficiency Virus