Cleavage strongly influences whether soluble HIV-1 envelope glycoprotein trimers adopt a native-like conformation.

TitleCleavage strongly influences whether soluble HIV-1 envelope glycoprotein trimers adopt a native-like conformation.
Publication TypeJournal Article
Year of Publication2013
AuthorsRinge RP, Sanders RW, Yasmeen A, Kim HJ, Lee J H, Cupo A, Korzun J, Derking R, van Montfort T, Julien J-P, Wilson IA, Klasse P J, Ward AB, Moore JP
JournalProc Natl Acad Sci U S A
Date Published11/05/2013
KeywordsAIDS Vaccines, Antibodies, Monoclonal, Electrophoresis, Polyacrylamide Gel, env Gene Products, Human Immunodeficiency Virus, HIV-1, Microscopy, Electron, Mutation, Missense, Protein Conformation, Protein Engineering, Protein Multimerization, Protein Subunits, Rosaniline Dyes

We compare the antigenicity and conformation of soluble, cleaved vs. uncleaved envelope glycoprotein (Env gp)140 trimers from the subtype A HIV type 1 (HIV-1) strain BG505. The impact of gp120-gp41 cleavage on trimer structure, in the presence or absence of trimer-stabilizing modifications (i.e., a gp120-gp41 disulfide bond and an I559P gp41 change, together designated SOSIP), was assessed. Without SOSIP changes, cleaved trimers disintegrate into their gp120 and gp41-ectodomain (gp41ECTO) components; when only the disulfide bond is present, they dissociate into gp140 monomers. Uncleaved gp140s remain trimeric whether SOSIP substitutions are present or not. However, negative-stain electron microscopy reveals that only cleaved trimers form homogeneous structures resembling native Env spikes on virus particles. In contrast, uncleaved trimers are highly heterogeneous, adopting a variety of irregular shapes, many of which appear to be gp120 subunits dangling from a central core that is presumably a trimeric form of gp41ECTO. Antigenicity studies with neutralizing and nonneutralizing antibodies are consistent with the EM images; cleaved, SOSIP-stabilized trimers express quaternary structure-dependent epitopes, whereas uncleaved trimers expose nonneutralizing gp120 and gp41ECTO epitopes that are occluded on cleaved trimers. These findings have adverse implications for using soluble, uncleaved trimers for structural studies, and the rationale for testing uncleaved trimers as vaccine candidates also needs to be reevaluated.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID24145402
PubMed Central IDPMC3831437
Grant ListP01 AI82362 / AI / NIAID NIH HHS / United States
P30 AI036214 / AI / NIAID NIH HHS / United States
P41 GM103310 / GM / NIGMS NIH HHS / United States
P41 RR017573 / RR / NCRR NIH HHS / United States
R01 AI84817 / AI / NIAID NIH HHS / United States
R37 AI036082 / AI / NIAID NIH HHS / United States
R37 AI36082 / AI / NIAID NIH HHS / United States
UM1 AI100663 / AI / NIAID NIH HHS / United States
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