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Retrovirology. 2014 Mar 13;11:24. doi: 10.1186/1742-4690-11-24.

Structural basis for the inhibition of HIV-1 Nef by a high-affinity binding single-domain antibody.

Author information

1
Center of Advanced European Studies and Research, Group Physical Biochemistry, Bonn, Germany. matthias.geyer@caesar.de.

Abstract

BACKGROUND:

The HIV-1 Nef protein is essential for AIDS pathogenesis by its interaction with host cell surface receptors and signaling factors. Despite its critical role as a virulence factor Nef is not targeted by current antiviral strategies.

RESULTS:

We have determined the crystal structure of the complex formed by a camelid single-domain antibody fragment, termed sdAb19, bound to HIV-1 Nef together with a stabilizing SH3 domain. sdAb19 forms a stoichiometric 1:1 complex with Nef and binds to a conformationally conserved surface at the C-terminus of Nef that overlaps with functionally important interaction sites involved in Nef-induced perturbations of signaling and trafficking pathways. The antibody fragment binds Nef with low nanomolar affinity, which could be attenuated to micromolar affinity range by site-directed mutagenesis of key interaction residues in sdAb19. Fusion of the SH3 domain to sdAb19, termed Neffin, leads to a significantly increased affinity for Nef and formation of a stoichiometric 2:2 Nef-Neffin complex. The 19 kDa Neffin protein inhibits all functions of Nef as CD4 and MHC-I downregulation, association with Pak2, and the increase in virus infectivity and replication.

CONCLUSIONS:

Together, sdAb19 and Neffin thus represent efficient tools for the rational development of antiviral strategies against HIV-1 Nef.

PMID:
24620746
PMCID:
PMC4007562
DOI:
10.1186/1742-4690-11-24
[Indexed for MEDLINE]
Free PMC Article

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