title: Phenotype-associated sequence variation in the third variable domain of the human immunodeficiency virus type 1 gp120 molecule.
abstract: The third variable (V3) domain has been implicated in determining the human immunodeficiency virus (HIV) phenotype, including fusion capacity and monocytotropism. In a large set of primary HIV type 1 (HIV-1) isolates, V3 sequence analysis revealed that fast-replicating, syncytium-inducing isolates contained V3 sequences with a significantly higher positive charge than those of slow-replicating, non-syncytium-inducing monocytotropic isolates. It appeared that these differences in charge could be attributed to highly variable amino acid residues located on either side of the V3 loop, midway between the cysteine residues and the central GPG motif. In non-syncytium-inducing monocytotropic isolates, these residues were negatively charged or uncharged, whereas in syncytium-inducing nonmonocytotropic isolates, either one or both were positively charged. The substitutions at these positions result in changes in the predicted secondary structure of the V3 loop. Our data suggest that two amino acid residues in the highly variable V3 domain are responsible for phenotype differences and point to conformational differences in V3 loops from phenotypically distinct HIV-1 isolates.
authors.affiliation: Department of Clinical Viro-Immunology, Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, Amsterdam.
authors.forename: R A
authors.initials: RA
authors.lastname: Fouchier
authors.forename: M
authors.initials: M
authors.lastname: Groenink
authors.forename: N A
authors.initials: NA
authors.lastname: Kootstra
authors.forename: M
authors.initials: M
authors.lastname: Tersmette
authors.forename: H G
authors.initials: HG
authors.lastname: Huisman
authors.forename: F
authors.initials: F
authors.lastname: Miedema
authors.forename: H
authors.initials: H
authors.lastname: Schuitemaker
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000235:genetics*; D000595:Amino Acid Sequence; D002459:Cell Fusion / Q000187:drug effects; D014644:Genetic Variation; D015699:HIV Envelope Protein gp120 / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010641:Phenotype; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid; D013329:Structure-Activity Relationship
chemical_list: D015699:HIV Envelope Protein gp120