title: Interaction of the gp120 V1V2 loop with a neighboring gp120 unit shields the HIV envelope trimer against cross-neutralizing antibodies.
abstract: The HIV-1 envelope trimer adopts a quaternary conformation that effectively shields neutralization-sensitive domains and thus represents a major obstacle for natural and vaccine-elicited antibody responses. By using a structure-function analysis based on a specifically devised mathematical model, we demonstrate in this study that protection from neutralization is enforced by intersubunit contact between the variable loops 1 and 2 (V1V2) and domains of neighboring gp120 subunits in the trimer encompassing the V3 loop. Our data are consistent with an interaction of the V1V2 and V3 loop at the spike apex as proposed by cryoelectron tomography experiments. By defining the orientation of the V1V2 loop within the trimer toward the neighboring gp120 subunit's V3 loop, our data close an important gap in the understanding of the architecture of the trimeric spike. Knowledge on how the V1V2 barrier functions in the context of the trimer to mask conserved epitopes on gp120 may aid future vaccine design.
authors.affiliation: Institute of Medical Virology, University Hospital Zurich; University of Zurich, 8006 Zurich, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Rusert
authors.forename: Anders
authors.initials: A
authors.lastname: Krarup
authors.forename: Carsten
authors.initials: C
authors.lastname: Magnus
authors.forename: Oliver F
authors.initials: OF
authors.lastname: Brandenberg
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Weber
authors.forename: Anna-Katharina
authors.initials: AK
authors.lastname: Ehlert
authors.forename: Roland R
authors.initials: RR
authors.lastname: Regoes
authors.forename: Huldrych F
authors.initials: HF
authors.lastname: Günthard
authors.forename: Alexandra
authors.initials: A
authors.lastname: Trkola
mesh_terms: D000595:Amino Acid Sequence; D057134:Antibodies, Neutralizing; D001483:Base Sequence; D002460:Cell Line; D003429:Cross Reactions; D004279:DNA, Viral / Q000235:genetics; D000939:Epitopes / Q000737:chemistry; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015497:HIV-1 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D006801:Humans; D018448:Models, Immunological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D054730:Protein Interaction Domains and Motifs; D020836:Protein Structure, Quaternary
chemical_list: D057134:Antibodies, Neutralizing; D004279:DNA, Viral; D000939:Epitopes; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; C059761:HIV envelope protein gp120 (135-148); D010446:Peptide Fragments