Format

Send to

Choose Destination
Biophys J. 2019 Apr 23;116(8):1432-1445. doi: 10.1016/j.bpj.2019.03.014. Epub 2019 Mar 23.

Conformational Dynamics of the HIV-Vif Protein Complex.

Author information

1
Department of Chemistry, Skidmore College, Saratoga Springs, New York. Electronic address: kball@skidmore.edu.
2
Department of Chemistry, Skidmore College, Saratoga Springs, New York.
3
Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California.
4
Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California. Electronic address: jdgross@cgl.ucsf.edu.

Abstract

Human immunodeficiency virus-1 viral infectivity factor (Vif) is an intrinsically disordered protein responsible for the ubiquitination of the APOBEC3 (A3) antiviral proteins. Vif folds when it binds Cullin-RING E3 ligase 5 and the transcription cofactor CBF-β. A five-protein complex containing the substrate receptor (Vif, CBF-β, Elongin-B, Elongin-C (VCBC)) and Cullin5 (CUL5) has a published crystal structure, but dynamics of this VCBC-CUL5 complex have not been characterized. Here, we use molecular dynamics (MD) simulations and NMR to characterize the dynamics of the VCBC complex with and without CUL5 and an A3 protein bound. Our simulations show that the VCBC complex undergoes global dynamics involving twisting and clamshell opening of the complex, whereas VCBC-CUL5 maintains a more static conformation, similar to the crystal structure. This observation from MD is supported by methyl-transverse relaxation-optimized spectroscopy NMR data, which indicates that the VCBC complex without CUL5 is dynamic on the μs-ms timescale. Our NMR data also show that the VCBC complex is more conformationally restricted when bound to the antiviral APOBEC3F (one of the A3 proteins), consistent with our MD simulations. Vif contains a flexible linker region located at the hinge of the VCBC complex, which changes conformation in conjunction with the global dynamics of the complex. Like other substrate receptors, VCBC can exist alone or in complex with CUL5 and other proteins in cells. Accordingly, the VCBC complex could be a good target for therapeutics that would inhibit full assembly of the ubiquitination complex by stabilizing an alternate VCBC conformation.

PMID:
30961890
PMCID:
PMC6486493
[Available on 2020-04-23]
DOI:
10.1016/j.bpj.2019.03.014

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center