Single-chain soluble BG505.SOSIP gp140 trimers as structural and antigenic mimics of mature closed HIV-1 Env

Ivelin S. Georgiev, M. Gordon Joyce, Yongping Yang, Mallika Sastry, Baoshan Zhang, Ulrich Baxa, Rita E. Chen, Aliaksandr Druz, Christopher R. Lees, Sandeep Narpala, Arne Schön, Joseph Van Galen, Gwo Yu Chuang, Jason Gorman, Adam Harned, Marie Pancera, Guillaume B.E. Stewart-Jones, Cheng Cheng, Ernesto Freire, Adrian B. McDermottJohn R. Mascola, Peter D. Kwong

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


Similar to other type I fusion machines, the HIV-1 envelope glycoprotein (Env) requires proteolytic activation; specifically, cleavage of a gp160 precursor into gp120 and gp41 subunits creates an N-terminal gp41 fusion peptide and permits folding from an immature uncleaved state to a mature closed state. While the atomic-level consequences of cleavage for HIV-1 Env are still being determined, the uncleaved state is antigenically distinct from the mature closed state, and cleavage has been reported to be essential for mimicry of the mature viral spike by soluble versions of Env. Here we report the redesign of a current state-of-the-art soluble Env mimic, BG505.SOSIP, to make it cleavage independent. Specifically, we replaced the furin cleavage site between gp120 and gp41 with Gly-Ser linkers of various lengths. The resultant linked gp120-gp41 constructs, termed single-chain gp140 (sc-gp140), exhibited different levels of structural and antigenic mimicry of the parent cleaved BG505.SOSIP. When constructs were subjected to negative selection to remove subspecies recognized by poorly neutralizing antibodies, trimers of high antigenic mimicry of BG505.SOSIP could be obtained; negative-stain electron microscopy indicated these to resemble the mature closed state. Higher proportions of BG505.SOSIP-trimer mimicry were observed in sc-gp140s with linkers of 6 or more residues, with a linker length of 15 residues exhibiting especially promising traits. Overall, flexible linkages between gp120 and gp41 in BG505.SOSIP can thus substitute for cleavage, and sc-gp140s that closely mimicked the vaccine-preferred mature closed state of Env could be obtained.

Original languageEnglish (US)
Pages (from-to)5318-5329
Number of pages12
JournalJournal of virology
Issue number10
StatePublished - 2015

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology


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