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M9490411.TXT
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1994-09-19
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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
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).