Glycine Substitution at Helix-to-Coil Transitions Facilitates the Structural Determination of a Stabilized Subtype C HIV Envelope Glycoprotein

Immunity. 2017 May 16;46(5):792-803.e3. doi: 10.1016/j.immuni.2017.04.014.


Advances in HIV-1 envelope glycoprotein (Env) design generate native-like trimers and high-resolution clade A, B, and G structures and elicit neutralizing antibodies. However, a high-resolution clade C structure is critical, as this subtype accounts for the majority of HIV infections worldwide, but well-ordered clade C Env trimers are more challenging to produce due to their instability. Based on targeted glycine substitutions in the Env fusion machinery, we defined a general approach that disfavors helical transitions leading to post-fusion conformations, thereby favoring the pre-fusion state. We generated a stabilized, soluble clade C Env (16055 NFL) and determined its crystal structure at 3.9 Å. Its overall conformation is similar to SOSIP.664 and native Env trimers but includes a covalent linker between gp120 and gp41, an engineered 201-433 disulfide bond, and density corresponding to 22 N-glycans. Env-structure-guided design strategies resulted in multiple homogeneous cross-clade immunogens with the potential to advance HIV vaccine development.

Keywords: Antibody; Envelope glycoprotein; Glycan shield; HIV; Immunogen; Trimer; Vaccine; bNAb.

Publication types

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

MeSH terms

  • Amino Acid Substitution*
  • Antibodies, Neutralizing / chemistry
  • Antibodies, Neutralizing / immunology
  • Antibodies, Neutralizing / metabolism
  • Binding Sites
  • Genotype
  • Glycine / chemistry*
  • Glycine / genetics
  • Glycosylation
  • HIV Antibodies / chemistry
  • HIV Antibodies / immunology
  • HIV Antibodies / metabolism
  • HIV Envelope Protein gp120 / chemistry
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / immunology
  • HIV Envelope Protein gp41 / chemistry
  • HIV Envelope Protein gp41 / genetics
  • HIV Envelope Protein gp41 / immunology
  • HIV-1 / classification
  • HIV-1 / genetics
  • HIV-1 / immunology*
  • Humans
  • Models, Molecular
  • Mutation
  • Protein Binding / immunology
  • Protein Conformation, alpha-Helical*
  • Protein Engineering
  • Protein Multimerization
  • Protein Stability
  • Proteolysis
  • Solubility
  • Structure-Activity Relationship
  • env Gene Products, Human Immunodeficiency Virus / chemistry*
  • env Gene Products, Human Immunodeficiency Virus / genetics
  • env Gene Products, Human Immunodeficiency Virus / immunology*


  • Antibodies, Neutralizing
  • HIV Antibodies
  • HIV Envelope Protein gp120
  • HIV Envelope Protein gp41
  • env Gene Products, Human Immunodeficiency Virus
  • Glycine