HIV-1 Envelope and MPER Antibody Structures in Lipid Assemblies

Cell Rep. 2020 Apr 28;31(4):107583. doi: 10.1016/j.celrep.2020.107583.

Abstract

Structural and functional studies of HIV envelope glycoprotein (Env) as a transmembrane protein have long been complicated by challenges associated with inherent flexibility of the molecule and the membrane-embedded hydrophobic regions. Here, we present approaches for incorporating full-length, wild-type HIV-1 Env, as well as C-terminally truncated and stabilized versions, into lipid assemblies, providing a modular platform for Env structural studies by single particle electron microscopy. We reconstitute a full-length Env clone into a nanodisc, complex it with a membrane-proximal external region (MPER) targeting antibody 10E8, and structurally define the full quaternary epitope of 10E8 consisting of lipid, MPER, and ectodomain contacts. By aligning this and other Env-MPER antibody complex reconstructions with the lipid bilayer, we observe evidence of Env tilting as part of the neutralization mechanism for MPER-targeting antibodies. We also adapt the platform toward vaccine design purposes by introducing stabilizing mutations that allow purification of unliganded Env with a peptidisc scaffold.

Keywords: HIV-1 Env; MPER broadly neutralizing antibody; bicelle; nanodisc; peptidisc.

Publication types

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

MeSH terms

  • HIV Envelope Protein gp41 / genetics*
  • HIV-1 / genetics*
  • Humans
  • Lipid Bilayers / metabolism*

Substances

  • HIV Envelope Protein gp41
  • Lipid Bilayers