Molecular insight into the conformational dynamics of the Elongin BC complex and its interaction with HIV-1 Vif.
The human immunodeficiency virus type 1 virion infectivity factor (Vif) inhibits the innate viral immunity afforded by the APOBEC3 family of cytidine deaminases. Vif targets the APOBEC3 family for poly-ubiquitination and subsequent proteasomal degradation by linking the Elongin-BC-dependent ubiquitin ligase complex with the APOBEC3 proteins. The interaction between Vif and the heterodimeric Elongin BC complex, which is mediated by Vif's viral suppressor of cytokine signaling box, is essential for Vif function. The biophysical consequences of the full-length Vif:Elongin BC interaction have not been extensively reported. In this study, hydrogen exchange mass spectrometry was used to dissect the Vif:Elongin BC interaction. Elongin C was found to be highly dynamic in the Elongin BC complex while Elongin B was much more stable. Recombinant full-length Vif interacted with the Elongin BC complex in vitro with a K(d) of 1.9 μM and resulted in observable changes in deuterium uptake in both Elongin C and B. Upon binding to Elongin BC, no significant global conformational changes were detected in Vif by hydrogen exchange mass spectrometry, but a short fragment of Vif that consisted of the viral suppressor of cytokine signaling box showed decreased deuterium incorporation upon Elongin BC incubation, suggesting that this region folds upon binding.
Marcsisin
Sean R
SR
Department of Chemistry and Chemical Biology and the Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, MA 02115, USA.
Engen
John R
JR
D000595:Amino Acid Sequence; D000075065:Elongin; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D025941:Protein Interaction Mapping; D020836:Protein Structure, Quaternary; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D054320:vif Gene Products, Human Immunodeficiency Virus / Q000737:chemistry* / Q000378:metabolism*
C000616396:ELOB protein, human; C000616395:ELOC protein, human; D000075065:Elongin; D014157:Transcription Factors; D054320:vif Gene Products, Human Immunodeficiency Virus; C514847:vif protein, Human immunodeficiency virus 1; D006859:Hydrogen