HIV-1 broadly neutralizing antibody extracts its epitope from a kinked gp41 ectodomain region on the viral membrane

Immunity. 2008 Jan;28(1):52-63. doi: 10.1016/j.immuni.2007.11.018.

Abstract

Although rarely elicited during natural human infection, the most broadly neutralizing antibodies (BNAbs) against diverse human immunodeficiency virus (HIV)-1 strains target the membrane-proximal ectodomain region (MPER) of viral gp41. To gain insight into MPER antigenicity, immunogenicity, and viral function, we studied its structure in the lipid environment by a combination of nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), and surface plasmon resonance (SPR) techniques. The analyses revealed a tilted N-terminal alpha helix (aa 664-672) connected via a short hinge to a flat C-terminal helical segment (675-683). This metastable L-shaped structure is immersed in viral membrane and, therefore, less accessible to immune attack. Nonetheless, the 4E10 BNAb extracts buried W672 and F673 after initial encounter with the surface-embedded MPER. The data suggest how BNAbs may perturb tryptophan residue-associated viral fusion involving the mobile N-terminal MPER segment and, given conservation of MPER sequences in HIV-1, HIV-2, and SIV, have important implications for structure-guided vaccine design.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Antigens, Viral / chemistry*
  • Antigens, Viral / immunology
  • Electron Spin Resonance Spectroscopy
  • HIV Antibodies / chemistry*
  • HIV Antibodies / immunology
  • HIV Envelope Protein gp41 / chemistry*
  • HIV Envelope Protein gp41 / immunology
  • Humans
  • Magnetic Resonance Spectroscopy
  • Protein Structure, Secondary
  • Surface Plasmon Resonance

Substances

  • Antigens, Viral
  • HIV Antibodies
  • HIV Envelope Protein gp41

Associated data

  • PDB/2PV6