Design, expression, and immunogenicity of a soluble HIV trimeric envelope fragment adopting a prefusion gp41 configuration.

Published

Journal Article

The human immunodeficiency virus-1 (HIV-1) envelope glycoprotein (Env) is comprised of non-covalently associated gp120/gp41 subunits that form trimeric spikes on the virion surface. Upon binding to host cells, Env undergoes a series of structural transitions, leading to gp41 rearrangement necessary for fusion of viral and host membranes. Until now, the prefusion state of gp41 ectodomain (e-gp41) has eluded molecular and structural analysis, and thus assessment of the potential of such an e-gp41 conformer to elicit neutralizing antibodies has not been possible. Considering the importance of gp120 amino (C1) and carboxyl (C5) segments in the association with e-gp41, we hypothesize that these regions are sufficient to maintain e-gp41 in a prefusion state. Based on the available gp120 atomic structure, we designed several truncated gp140 variants by including the C1 and C5 regions of gp120 in a gp41 ectodomain fragment. After iterative cycles of protein design, expression and characterization, we obtained a variant truncated at Lys(665) that stably folds as an elongated trimer under physiologic conditions. Several independent biochemical/biophysical analyses strongly suggest that this mini-Env adopts a prefusion e-gp41 configuration that is strikingly distinct from the postfusion trimer-of-hairpin structure. Interestingly, this prefusion mini-Env, lacking the fragment containing the 2F5/4E10 neutralizing monoclonal antibody binding sites, displays no detectable HIV-neutralizing epitopes when employed as an immunogen in rabbits. The result of this immunogenicity study has important implications for HIV-1 vaccine design efforts. Moreover, this engineered mini-Env protein should facilitate three-dimensional structural studies of the prefusion e-gp41 and serve to guide future attempts at pharmacologic and immunologic intervention of HIV-1.

Full Text

Duke Authors

Cited Authors

  • Qiao, Z-S; Kim, M; Reinhold, B; Montefiori, D; Wang, J-H; Reinherz, EL

Published Date

  • June 17, 2005

Published In

Volume / Issue

  • 280 / 24

Start / End Page

  • 23138 - 23146

PubMed ID

  • 15833740

Pubmed Central ID

  • 15833740

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.M414515200

Language

  • eng

Conference Location

  • United States