Interhelical interactions in the gp41 core: Implications for activation of HIV-1 membrane fusion

Shilong Wang, Joanne York, Wei Shu, Marisa O. Stoller, Jack H. Nunberg, Min Lu

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

The human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein complex (gp120-gp41) promotes viral entry by mediating the fusion of viral and cellular membranes. Formation of a stable trimer-of-hairpins structure in the gp41 ectodomain brings the two membranes into proximity, leading to membrane fusion. The core of this hairpin structure is a six-helix bundle in which three carboxyl-terminal outer helices pack against an inner trimeric coiled coil. Here we investigate the role of these conserved interhelical interactions on the structure and function of both the envelope glycoprotein and the gp41 core. We have replaced each of the eight amino acids at the buried face of the carboxyl-terminal helix with a representative amino acid, alanine. Structural and physicochemical characterization of the alanine mutants shows that hydrophobic interactions are a dominant factor in the stabilization of the six-helix bundle. Alanine substitutions at the Trp628, Trp631, Ile635, and Ile642 residues also affected envelope processing and/or gp120-gp41 association and abrogated the ability of the envelope glycoprotein to mediate cell-cell fusion. These results suggest that the amino-terminal region of the gp41 outer-layer α-helix plays a key role in the sequence of events associated with HIV-1 entry and have implications for the development of antibodies and small-molecule inhibitors of this conserved element.

Original languageEnglish (US)
Pages (from-to)7283-7292
Number of pages10
JournalBiochemistry
Volume41
Issue number23
DOIs
StatePublished - Jun 11 2002
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry

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