5KA6

HIV-1 gp41 variant Q552R and L555M resistance mutations


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.231 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Receptor Activation of HIV-1 Env Leads to Asymmetric Exposure of the gp41 Trimer.

Khasnis, M.D.Halkidis, K.Bhardwaj, A.Root, M.J.

(2016) PLoS Pathog. 12: e1006098-e1006098

  • DOI: 10.1371/journal.ppat.1006098
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Structural rearrangements of HIV-1 glycoprotein Env promote viral entry through membrane fusion. Env is a symmetric homotrimer with each protomer composed of surface subunit gp120 and transmembrane subunit gp41. Cellular CD4- and chemokine receptor-b ...

    Structural rearrangements of HIV-1 glycoprotein Env promote viral entry through membrane fusion. Env is a symmetric homotrimer with each protomer composed of surface subunit gp120 and transmembrane subunit gp41. Cellular CD4- and chemokine receptor-binding to gp120 coordinate conformational changes in gp41, first to an extended prehairpin intermediate (PHI) and, ultimately, into a fusogenic trimer-of-hairpins (TOH). HIV-1 fusion inhibitors target gp41 in the PHI and block TOH formation. To characterize structural transformations into and through the PHI, we employed asymmetric Env trimers containing both high and low affinity binding sites for individual fusion inhibitors. Asymmetry was achieved using engineered Env heterotrimers composed of protomers deficient in either CD4- or chemokine receptor-binding. Linking receptor engagement to inhibitor affinity allowed us to assess conformational changes of individual Env protomers in the context of a functioning trimer. We found that the transition into the PHI could occur symmetrically or asymmetrically depending on the stoichiometry of CD4 binding. Sequential engagement of multiple CD4s promoted progressive exposure of individual fusion inhibitor binding sites in a CD4-dependent fashion. By contrast, engagement of only a single CD4 molecule led to a delayed, but symmetric, exposure of the gp41 trimer. This complex coupling between Env-CD4 interaction and gp41 exposure explained the multiphasic fusion-inhibitor titration observed for a mutant Env homotrimer with a naturally asymmetric gp41. Our results suggest that the spatial and temporal exposure of gp41 can proceed in a nonconcerted, asymmetric manner depending on the number of CD4s that engage the Env trimer. The findings have important implications for the mechanism of viral membrane fusion and the development of vaccine candidates designed to elicit neutralizing antibodies targeting gp41 in the PHI.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, United States of America.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Transmembrane protein gp41
A, B, C
91Human immunodeficiency virus type 1 group M subtype B (isolate HXB2)Mutation(s): 2 
Gene Names: env
Find proteins for P04578 (Human immunodeficiency virus type 1 group M subtype B (isolate HXB2))
Go to UniProtKB:  P04578
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.85 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.231 
  • Space Group: P 31
Unit Cell:
Length (Å)Angle (°)
a = 43.591α = 90.00
b = 43.591β = 90.00
c = 113.048γ = 120.00
Software Package:
Software NamePurpose
PHENIXrefinement
PHASERphasing
Aimlessdata scaling
DIALSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited States5R01GM066682

Revision History 

  • Version 1.0: 2016-12-14
    Type: Initial release
  • Version 1.1: 2017-01-18
    Type: Database references
  • Version 1.2: 2017-09-13
    Type: Author supporting evidence