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PubMed · 8626517

Structure and polymorphism of HIV-1 third variable loops.

P Catasti·E M Bradbury·G Gupta
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Abstract

The third variable (V3) loop of HIV-1 surface glycoprotein, gp120, has been the target of neutralizing antibodies. However, sequence variation inside the V3 loop diminishes its effectiveness as a potential vaccine against HIV-1. The elusive nature of the V3 loop structure prompted us to carry out a systematic study on different isolates in an attempt to identify a common structural motif in the V3 loop regardless of the amino acid sequence variability. We have previously determined the structural features of two V3 loops: V3 Thailand and V3 MN. In this paper, we present the structure of two other variants: V3 Haiti and V3 RF. Our results show that similar secondary structures are observed in all the four V3 loops: a GPG(R/K/Q) crest in the center of the neutralizing domain, two extended regions flanking the central crest, and a helical region in the C-terminal domain. For the Haitian V3 loop, we also show how the conserved structural features are masked through a conformational switch encoded in the amino acid sequences on the C-terminal side of the GPGK crest.

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Amino Acid SequenceHIV Envelope Protein gp120HIV-1Hydrogen BondingMagnetic Resonance SpectroscopyModels, MolecularMolecular Sequence DataProtein FoldingProtein Structure, SecondaryProtein Structure, TertiarySolventsTrifluoroethanolWaterJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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P Catasti, E M Bradbury, G Gupta. 1996-04-05. Structure and polymorphism of HIV-1 third variable loops.. https://doi.org/10.1074/jbc.271.14.8236

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