title: Identification of ENV determinants in V3 that influence the molecular anatomy of CCR5 utilization.
abstract: The V3 loop of the ENV glycoprotein exerts a dominant influence on the interaction of gp120 with coreceptors. Primary env genes cloned from sequential isolates from two seroconverters revealed Pro-->Ala conversion in the conserved GPG motif of the V3 crown in seven of 17 R5 ENV. ENV containing the GPG motif in the V3 crown had fusogenic activity with chimeric receptors containing either the N terminus or loops of CCR5, whereas those with the GAG variant utilized only the former. Site-directed mutagenesis of multiple primary and prototypic R5 env genes demonstrated that the GPG motif was necessary for dual utilization of the N terminus and body of CCR5 in both gain and loss-of-function experiments. All ENV containing the GPG V3 crown showed CCR5 binding in the presence of soluble CD4, whereas it was not detected with the GAG variants. Molecular dynamic simulations of a V3 peptide predicts that the Pro-->Ala substitution results in a conformational change with loss of the crown structure. These studies demonstrate that sequences in the third hypervariable region determine the specificity of coreceptor utilization for fusion, and that a conserved motif in the crown directly influences the molecular anatomy of the interaction between gp120 and CCR5.
authors.affiliation: Henry Vogt Cancer Research Institute, James Graham Brown Cancer Center, Louisville, KY, 40202, USA. huqinxue@hotmail.com
authors.forename: Q
authors.initials: Q
authors.lastname: Hu
authors.forename: J O
authors.initials: JO
authors.lastname: Trent
authors.forename: G D
authors.initials: GD
authors.lastname: Tomaras
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: J L
authors.initials: JL
authors.lastname: Murray
authors.forename: S M
authors.initials: SM
authors.lastname: Conolly
authors.forename: J M
authors.initials: JM
authors.lastname: Navenot
authors.forename: A P
authors.initials: AP
authors.lastname: Barry
authors.forename: M L
authors.initials: ML
authors.lastname: Greenberg
authors.forename: S C
authors.initials: SC
authors.lastname: Peiper
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D001665:Binding Sites; D015704:CD4 Antigens / Q000378:metabolism; D002459:Cell Fusion; D002460:Cell Line; D017930:Genes, Reporter / Q000235:genetics; D015752:Genes, env / Q000235:genetics; D014644:Genetic Variation / Q000235:genetics; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D011487:Protein Conformation; D019713:Receptors, CCR5 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D012995:Solubility; D013379:Substrate Specificity; D014162:Transfection
chemical_list: D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D010446:Peptide Fragments; D019713:Receptors, CCR5; D011993:Recombinant Fusion Proteins