Document 0411
 DOCN  M9490411
 TI    Characterization of human immunodeficiency virus type 1 gp120 binding to
       liposomes containing galactosylceramide.
 DT    9411
 AU    Long D; Berson JF; Cook DG; Doms RW; Department of Pathology and
       Laboratory Medicine, University of; Pennsylvania Medical Center,
       Philadelphia 19104.
 SO    J Virol. 1994 Sep;68(9):5890-8. Unique Identifier : AIDSLINE
       MED/94335106
 AB    Human immunodeficiency virus type 1 (HIV-1) infects some cell types
       which lack CD4, demonstrating that one or more alternative viral
       receptors exist. One such receptor is galactosylceramide (GalCer), a
       glycosphingolipid distributed widely in the nervous system and in
       colonic epithelial cells. Using a liposome flotation assay, we found
       that the HIV-1 surface glycoprotein, gp120, quantitatively bound to
       liposomes containing GalCer but not to liposomes containing
       phospholipids and cholesterol alone. Binding was saturable and was
       inhibited by preincubating liposomes with anti-GalCer antibodies. We
       observed less efficient binding of gp120 to liposomes containing
       lactosylceramide, glucosylceramide, and galactosylsulfate, whereas no
       binding to liposomes containing mixed gangliosides, psychosine, or
       sphingomyelin was detected. Binding to GalCer was rapid, largely
       independent of temperature and pH, and stable to conditions which remove
       most peripheral membrane proteins. By contrast, gp120 bound to
       lactosylceramide could be removed by 2 M potassium chloride or 3 M
       potassium thiocyanate, demonstrating a less stable interaction. Removal
       of N-linked oligosaccharides on gp120 did not affect binding efficiency.
       However, as previously observed for CD4 binding, heat denaturation of
       gp120 prevented binding to GalCer. Finally, binding was critically
       dependent on the concentration of GalCer in the target membrane,
       suggesting that binding to glycolipid-rich domains occurs and that
       GalCer conformation may be important for gp120 recognition.
 DE    Galactosylceramides/*METABOLISM  Hydrogen-Ion Concentration  HIV
       Envelope Protein gp120/CHEMISTRY/*METABOLISM  HIV-1/*METABOLISM  In
       Vitro  Liposomes  Osmolar Concentration  Protein Binding
       Structure-Activity Relationship  Support, Non-U.S. Gov't  Support, U.S.
       Gov't, P.H.S.  Temperature  Time Factors  JOURNAL ARTICLE

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