Model Building and Refinement of a Natively Glycosylated HIV-1 Env Protein by High-Resolution Cryoelectron Microscopy

Structure. 2015 Oct 6;23(10):1943-1951. doi: 10.1016/j.str.2015.07.020. Epub 2015 Sep 17.


Secretory and membrane proteins from mammalian cells undergo post-translational modifications, including N-linked glycosylation, which can result in a large number of possible glycoforms. This sample heterogeneity can be problematic for structural studies, particularly X-ray crystallography. Thus, crystal structures of heavily glycosylated proteins such as the HIV-1 Env viral spike protein have been determined by removing the majority of glycans. This step is most frequently carried out using Endoglycosidase H (EndoH) and requires that all expressed glycans be in the high-mannose form, which is often not the native glycoform. With significantly improved technologies in single-particle cryoelectron microscopy, we demonstrate that it is now possible to refine and build natively glycosylated HIV-1 Env structures in solution to 4.36 Å resolution. At this resolution we can now analyze the complete epitope of a broadly neutralizing antibody (bnAb), PGT128, in the context of the trimer expressed with native glycans.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Neutralizing / chemistry*
  • Antibodies, Neutralizing / metabolism
  • Binding Sites
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • Epitopes / chemistry*
  • Epitopes / metabolism
  • Gene Expression
  • Glycosylation
  • HIV Antibodies / chemistry*
  • HIV Antibodies / metabolism
  • HIV-1 / genetics
  • HIV-1 / metabolism*
  • Models, Molecular
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Protein Processing, Post-Translational*
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • env Gene Products, Human Immunodeficiency Virus / chemistry*
  • env Gene Products, Human Immunodeficiency Virus / genetics
  • env Gene Products, Human Immunodeficiency Virus / metabolism


  • Antibodies, Neutralizing
  • Epitopes
  • HIV Antibodies
  • Recombinant Proteins
  • env Gene Products, Human Immunodeficiency Virus

Associated data

  • PDB/5ACO