Alternative Conformations of HIV-1 V3 Loops Mimic beta Hairpins in Chemokines, Suggesting a Mechanism for Coreceptor Selectivity.
Sharon, M., Kessler, N., Levy, R., Zolla-Pazner, S., Gorlach, M., Anglister, J.(2003) Structure 11: 225-236
- PubMed: 12575942 
- DOI: https://doi.org/10.1016/s0969-2126(03)00011-x
- Primary Citation of Related Structures:  
1NIZ, 1NJ0 - PubMed Abstract: 
The V3 loop of the HIV-1 envelope glycoprotein gp120 is involved in binding to the CCR5 and CXCR4 coreceptors. The structure of an HIV-1(MN) V3 peptide bound to the Fv of the broadly neutralizing human monoclonal antibody 447-52D was solved by NMR and found to be a beta hairpin. This structure of V3(MN) was found to have conformation and sequence similarities to beta hairpins in CD8 and CCR5 ligands MIP-1alpha, MIP-1beta, and RANTES and differed from the beta hairpin of a V3(IIIB) peptide bound to the strain-specific murine anti-gp120(IIIB) antibody 0.5beta. In contrast to the structure of the bound V3(MN) peptide, the V3(IIIB) peptide resembles a beta hairpin in SDF-1, a CXCR4 ligand. These data suggest that the 447-52D-bound V3(MN) and the 0.5beta-bound V3(IIIB) structures represent alternative V3 conformations responsible for selective interactions with CCR5 and CXCR4, respectively.
Organizational Affiliation: 
Department of Structural Biology, The Weizmann Institute of Science, 76100, Rehovot, Israel.